Bulletin of Environmental Science and Sustainable Management (e-ISSN 2716-5353)
Bulletin of Environmental Science & Sustainable Management (e-ISSN 2716-5353) (previously known as Bulletin of Environmental Science & Management) publishes research papers, short communications, mini review and review articles on all aspects of basic and applied research in environmental science and management with a focus on sustainable science and sustainable management, namely water quality monitoring, spatial and temporal distribution of pollutants, treatment technologies, modeling, water management, environmental law and many other related scopes. Authors wishing to submit their manuscript to this journal please email their manuscripts to the Editor-in-Chief ahmadrazi@ukm.edu.my.
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The evaluation of Periophtalmodon schlosseri as a source of acetylcholinesterase for the detection of insecticides
The aim of this study is to investigate the ability of acetylcholinesterase from mudskipper, Periophtalmodon schlosseri, as an assay to detect various pesticides, especially carbamate and organophosphate, and selected metal ions. The assay is sensitive to several carbamates with IC50of 0.0993, 0.0945, 0.0532 and 0.0488 mg/L for carbaryl, methomyl, propoxur and bendiocarb, respectively. Carbofuran highly inhibited the activity (0.0313) with the limit of detection (LOD) of 0.0176 and the limit of quantitation (LOQ) of 0.0526. The organophosphate group is less inhibiting compared to carbamate group.
Copyright (c) 2013 Bulletin of Environmental Science and Sustainable Management (e-ISSN 2716-5353) http://creativecommons.org/licenses/by/4.0
Isolation and Characterization of a heavy metal-tolerant diesel oil - degrading strain
A diesel-degrading bacterium has been isolated from a local university soil. The isolate was tentatively identified as Burkholderia sp. strain DRY27 based on the carbon utilization profiles using Biolog GN plates and partial 16S rDNA molecular phylogeny. Isolate 27 showed an increase cellular growth with respect to diesel concentrations from 0% until 3% where the optimum growth occurring at 3% (v/v) diesel concentration. Based on the optimization studies, sodium nitrate proved to be the best nitrogen source. Sodium nitrate was optimum at 7.7 gl-1 .The optimal temperature and optimal pH for this bacterium was between 10 to 40 oC and pH 7.5 to pH 8.5 respectively. Diesel components was proven to be completely removed from the reduction in the hydrocarbon peaks monitored by Solid Phase Microextraction Gas Chromatography analysis. These prove that this bacterium is the right bacterium for bioremediation of diesel spills and pollution in the tropics.
Entrapment of Mo-Reducing Bacterium Increase Its Resistance towards Heavy Metals
Molybdenum is highly toxic to ruminant at several ppm. Molybdenum pollution in soil and mine tailings could reach 20,000 ppm in the most contaminated region. Molybdenum is mined as a byproduct of copper in malaysia and occasional elevated levels of these heavy metals have been reported. Bioremediation of molybdenum in the presence of the toxic copper is a challenge. In this work a novel method of molybdenum removal from aqueous solution using the dialysis tubing method coupled with molybdenum-reducing activity of serratia sp. Strain dry5 is demonstrated. The enzymatic reduction of molybdenum is molybdenum blue, a colloid that does not pass through dialysis tubing. The calculated maximal rate of molybdenum blue production (vmobluemax) was 0.264±0.034 mmole/mo-blue/hr and the concentration of molybdate resulting in the half- maximal rate of reduction (kmo) was 21.78±3.89 mM molybdate indicating an efficient system with high tolerance towards molybdenum. Heavy metals exhibited significantly higher inhibition towards free cells compared to dialysis tubing entrapped cells. Hence the immobilization of mo- reducing cells by entrapment could be a viable bioremediation tool in aquatic bodies or effluent co-contaminated by other heavy metals.
An Iron Determination Method for Azo Dyes-Contaminated Wastewater
We have designed an improved iron determination method based on the ability of ferrous iron to reduce 12-molybdophosphate (12-MP). The method allows for direct determination of ferrous iron in the presence of azo dyes. The iron determination method had a specific extinction coefficient of 0.0514 (mg l-)-1.cm-1 at 865 nm with a correlation coefficient of 0.999. The relative standard deviation for each data point does not exceed 5% (n=3) suggesting precision. In its oxidized state 12-MP is yellowish in color and when reduced it forms a blue solution. The iron determination method is less interfered with azo dyes compared to common iron determination methods such as 1,10-phenanthroline and the commercial FerreMoTM.
An inhibitive assay for insecticides using the acetylcholinesterase from Osteochillus hasselti
The aim of this study is to investigate the ability of acetylcholinesterase from fresh water carp, Osteochillus hasseltias an assay to detect insecticides.The IC50 values for the carbamates carbofuran, carbaryl, methomyl, bendiocarb were 0.0550, 0.0497, 0.0845, 0.0470µg/l, respectively, and the IC50 values for the oxonated organophosphates parathion, malathion, diazinon and chlorpyrifos were 0.0660, 0.0681, 0.0991 and 0.0632µg/l, respectively. The carbamates carbaryl, and the oxonated organophosphate diazinon showed lower IC50s in O. hasselti compared to E. electricus while parathion and diazinon showed similar sensitivity to E. electricus. Carbofuran, methomyl, bendiocarb and malathion exhibited lower IC50 confidence interval in E. electricus than in O. hasselti. This suggests that in overall, AChE from Osteochillus hasseltiis a suitable source of enzyme for the detection of insecticides.
Characterization of a Molybdenum-reducing Burkholderia sp. Dr.Y27 with Phenol and Acrylamide-degrading Capability
Recent studies have shown that molybdenum is toxic to the process of spermatogenesis at concentrations of several parts per million, highlighting its significance as a toxic substance. We have previously identified a bacterium that has the ability to break down acrylamide in soils that have been contaminated. We found that this bacterium has the capability to convert the heavy metal molybdenum into molybdenum blue. The study examines the Mo-blue absorption spectra of Burkholderia sp. Dr. Y27, revealing a secondary peak at 700 nm and a primary peak ranging from 860 to 870 nm. It indicates that Mo-blue is probably a diminished heteropolymolybdate, aided by enzymatic reduction in media containing phosphate. The most favorable pH for molybdate reduction was determined to be approximately 6.0, while the optimal temperature range was found to be between 34 and 37°C. Multiple carbon sources were examined, and it was found that glucose, fructose, and 2-ketogluconate exhibited the greatest efficacy. The presence of heavy metals such as mercury and copper greatly suppressed the production of Mo-blue. This text discusses the potential of using bioremediation in tropical regions, specifically focusing on the ability of Burkholderia sp. Dr. Y27 to efficiently reduce molybdenum under optimal conditions. The results provide evidence for the capability of Burkholderia sp. Dr. Y27 to be a successful agent for molybdenum bioremediation, particularly in tropical settings, by optimizing factors such as pH, temperature, and carbon sources. Additional investigation is advised to examine its utilization in practical contexts.
Copyright (c) 2024 Bulletin of Environmental Science and Sustainable Management (e-ISSN 2716-5353) http://creativecommons.org/licenses/by/4.0
Characterization of a Metanil Yellow-decolorizing Pseudomonas strain Isolated from the Juru Industrial Park
This study examines how the initial concentration of dye, temperature, pH, and NaCl content affect the ability of a bacterial strain, specifically identified as Pseudomonas sp. strain UPM291, to remove color from Metanil Yellow. The decolorization percentage exhibited a distinct trend throughout a range of dye concentrations (0-700 mg/L), with the greatest efficacy (90-100%) recorded at values below 200 mg/L. The efficiency declined at higher concentrations, reaching approximately 20% at a dosage of 700 mg/L. Temperature investigations unveiled a symmetrical curve resembling a bell shape, indicating a range of temperatures that is most favorable for the process of decolorization. The maximum efficiency, approaching 100%, was found at a temperature of 35°C. However, the efficiency decreased considerably as the temperature above 35°C, reaching approximately 20% at 50°C. The impact of pH on decolorization exhibited comparable patterns, with optimal efficacy observed at pH 6.5 and diminished efficacy at both more acidic and more alkaline settings. The decolorization efficiency reached its peak (90-100%) at a pH of 6.5 and decreased to approximately 60% at a pH of 8.0. The influence of the NaCl content on decolorization was shown to follow a certain pattern, with the most effective decolorization (90-100%) occurring at NaCl concentrations of up to 10 g/L. The efficiency declined as the NaCl concentrations increased, reaching around 20% at 30 g/L. The data indicate that the bacterial strain demonstrates the highest effectiveness in removing color within particular ranges of dye concentration, temperature, pH, and NaCl content. There is a noticeable decline in efficiency when the parameters go outside of these optimal ranges. Gaining a comprehensive understanding of these characteristics can assist in optimizing the conditions necessary for the efficient bioremediation of Metanil Yellow utilizing specific bacterial strains.
Response Surface Method for the Optimization of Glyphosate Degrada-tion by Bacillus sp. Isolated from Soils Near Lake Maninjau
The study utilized a Box-Behnken experimental design to assess the impact of three parameters on the percentage of glyphosate biodegradation by a bacterium. The variables examined were incuba-tion period (measured in days), glyphosate concentration (measured in grams per liter), and pH, each assessed at three different levels. The quadratic model, which has squared terms, interaction products, linear terms, and an intercept, most accurately characterizes the connection between the variables and the response. The findings demonstrated that glyphosate concentration exerted the most pronounced impact on glyphosate degradation, with pH ranking second, as supported by substantial F-values and low p-values. The incubation period had no discernible effect. The ANOVA analysis validated the dependability of the model, as evidenced by an R² value of 0.9602 and an adjusted R² value of 0.9091. These values indicate that the model accounts for 90% of the variability observed in the response data. The contour and response surface plots demon-strated substantial interactions among the variables, specifically between pH and glyphosate con-centration and between the incubation period and glyphosate concentration. The model's anticipat-ed optimal conditions were experimentally tested, demonstrating no significant deviation from the projected values. The predicted maximum biodegradation of 90.097% closely matched the exper-imentally observed value of 92.505% (p>0.05). The predicted combination to give the desired maximum response was at pH 6.81, glyphosate concentration of 0.692 g/L and an incubation period of 3.092 days. On the other hand, the predicted combination to give the desired maximum response is based on the requirement for the conditions where biodegradation is at the highest possible glyphosate concentration of 0.844 g/L and an incubation period of 3.112 days. A higher response of about 5.779% degradation was achieved through RSM. This study showcases the efficacy of the Box-Behnken design in optimizing biodegradation processes, offering a solid sta-tistical basis for further investigations on glyphosate degradation.
Isolation and Characterization of a Diesel-degrading Bacterium From Waters Near the Langkawi UNESCO Kilim Karst Geoforest Park
This study explored the biodegradation potential of bacterial isolates from various locations in Malaysia, focusing on their ability to utilize diesel as a carbon source. Among the ten isolates tested, isolate 4, identified as Pseudomonas sp. strain UPM-Langkawi 3 based on morphological, cultural, and biochemical properties, exhibited significant growth on 2.5% diesel, indicating rapid activation of diesel assimilation mechanisms. Using the ABIS online software analysis, the strain was provisionally identified as Pseudomonas sp. UPM-Langkawi 3. Experimental results demonstrated that the optimal conditions for the growth of strain UPM-Langkawi 3 were between 6 and 8 % (v/v) diesel concentration, a temperature of between 28 and 35 °C, and a pH range of between 7.5 to 8.5. The strain showed inhibited growth at higher diesel concentrations and temperatures above 40 °C, as well as at a lower pH of 5.7. Among several inorganic nitrogen sources tested, 0.9% w/v ammonium sulphate was found to be the most effective, corroborating previous research. The study underscores the efficacy of Pseudomonas sp. strain UPM-Langkawi 3 in degrading diesel, suggesting its potential use in bioremediation of diesel-contaminated environments. Further research should employ molecular identification techniques, such as 16srRNA gene sequencing, to confirm the species identity and optimize biodegradation conditions. This work establishes a foundation for utilizing indigenous bacterial strains in environmental management strategies, particularly for areas impacted by hydrocarbon pollutants.
Characterization of a Pseudomonas sp. Isolated from Langkawi Capable of Degrading Glyphosate
Bioremediation of soil contaminants, including glyphosate, is an economically viable and environmentally friendly technique. Glyphosate, one of the most widely used herbicides for weed management, poses significant risks to wildlife and their habitats when it contaminates the environment. This study focused on the bioremediation potential of soil Pseudomonas spp. isolated from a paddy field with a long history of glyphosate application. The most promising isolate was tentatively identified as Pseudomonas sp. strain UPM-2009 through partial identification methods. This bacterium showed significant potential for glyphosate degradation under optimal conditions. Experiments demonstrated that Pseudomonas sp. degrades glyphosate most effectively at pH 7.0, a glyphosate concentration of 0.5 g/L, temperatures between 30 and 35°C, and an inoculum size of 1% (v/v). Notably, the bacterium exhibited a two-day lag period at 0.5 g/L glyphosate, achieving nearly 90% degradation after six days of incubation. Heavy metals such as Hg(II), Ag(I), and Cd(II) significantly inhibited bacterial growth, with inhibition rates of 99%, 95%, and 66%, respectively. This study underscores the potential of Pseudomonas sp. for bioremediation of glyphosate-contaminated environments. It highlights the need for further research, particularly molecular identification techniques, to fully characterize and optimize this bioremediation strategy. This approach can significantly contribute to mitigating the environmental impact of glyphosate pollution, promoting healthier ecosystems and sustainable agricultural practices.
Modeling the Degradation Rate of the Azo Dye Congo Red by Acinetobacter baumannii
One of the challenges that face the textile industry is the release of effluents that are not wanted, most notably colors that do not degrade. This is one of the issues that plagues the industry. This is a concern since it affects the environment. Bioremediation using dye-degrading bacterium is appealing as bacterial metabolism converts hazardous dye to harmless carbon dioxide and water as byproducts. In this study, various secondary growth models such as Luong, Yano, Teissier-Edward, Aiba, Haldane, Monod, Han, and Levenspiel were employed. Following thorough statistical analyses such as root-mean-square error (RMSE), adjusted coefficient of determination (adjR2), bias factor (BF), and accuracy factor (AF), the Luong model emerged as the most optimal choice. The half-saturation constant for maximal growth, maximal growth rate and maximal concentration of substrate tolerated and curve parameter that defines the steepness of the growth rate decline from the maximum rate symbolized by Ks, qmax and Sm, and n were 76.54 mg/L (95% C.I., 50.51 to 102.57), 0.240 per h (95% C.I., 0.219 to 0.270), 1135.37 mg/L (95% C.I., 1041.04 to 1229.72) and 5.34 (95% C.I., 2.36 to 8.32), respectively. These novel constants discovered during the modeling process could serve as valuable inputs for subsequent modeling pursuits.
A Near-Real-Time Ficin-Based Enzyme Assay for Biomonitoring of Heavy Metals Pollution in Waters Near the Langkawi UNESCO Kilim Karst Geoforest Park
Near-real-time biomonitoring, especially when utilizing enzyme assays, offers exceptional sensitivity to bioavailable pollutants, yielding swift results favorable to immediate action. This approach is particularly crucial in the context of mitigating pollution in drinking water systems, safeguarding both human and animal health. This study presents an application of a previously developed enzyme assay in biomonitoring to detect pollutants, specifically heavy metals, in environmental samples from the UNESCO’s Kilim Karst Geoforest Park. Utilizing the ficin dye binding assay, developed for mercury (Hg2+), silver (Ag+), and copper (Cu2+) detection at the sub ppm level, we demonstrated its effectiveness in identifying low concentrations of these metals in marine and brackish waters. The assay provided a sensitive, rapid, and cost-effective monitoring, showing negligible inhibition (<10%) over a 6-hour field trial, indicating low pollution levels and verified using instrumental analysis. This approach enables the early detection of environmental contaminants, facilitating timely interventions and contributing to the protection of ecotourism sites by providing evidence-based data for policymaking. The simplicity and visual appeal of the enzyme assays also make them excellent educational tools, promoting environmental awareness and conservation efforts. Our findings underscore the potential of enzyme assays for widespread environmental assessment, aligning local monitoring practices with international standards and fostering global collaboration in environmental protection. This study not only contributes to our understanding of ecological health in marine and brackish waters but also highlights the importance of continuous monitoring to preserve natural habitats.
Frame and Catch Assessment Surveys of the Fisheries of Egbe Reservoir, Ekiti State, Nigeria
Frame and Catch Assessments of surveys of the fisheries of the Egbe reservoir were conducted to provide data needed for its management and development. Descriptive statistics was used to analyze the data. A total of 2748 fish species were assessed. 57 fishermen were recorded. Sixty wooden canoes were counted and recorded. Fishing gears recorded included (380) gill nets, (19) cast nets, (77) long lines, (1008) Malian fish traps, (3879) wire fish traps, and (13) spares. About 7 fish species from 5 families were identified. Cichlidae was the most relatively abundant family, contributing 75.9% to the number and 71.7% to the weight of the total fish caught on the reservoir, while Mormyridae was the lowest abundant family, accounting for 0.58% and 0.15% in terms of number and weight respectively of the total fish caught. The current fish yield of the reservoir is 17.5 metric tonnes per annum. This corresponds to 64.2 kg/ha and is considered low. Recommendations were made for the management and development of the reservoir fisheries.
Primary Modeling of Microbial Growth under Toxic Conditions with the Modified Schnute Model
Primary modeling of microbial growth is essential for determining key parameters such as the maximum specific growth rate (μm), which are foundational for secondary modeling. These models, including those by Monod, Haldane, Aiba, and Teissier, elucidate the impact of substrates on bacterial growth and biotransformation processes, vital for biotechnological applications like wastewater treatment and bioremediation. Experimental data showed that acrylamide from 250 to 1250 mg/L as a sole nitrogen source is toxic, slowing bacterial growth at higher concentrations resulting in an increase in lag periods ranging from 3 to 9 hours. Various primary models were tested, with the modified Schnute model providing the best fit based on statistical analysis, normality tests, and key parameters such as adjusted coefficient of determination near to unity, lowest values for RMSE and AICc values and good values of accuracy (AF) and bias factors (BF). The modified Schnute model's reliability underscores its suitability for modeling bacterial growth under toxic conditions, offering valuable insights for optimizing biotechnological processes involving bacterial adaptation and growth under stress conditions.
Time-Series Assessment of Vegetation Structure and Compositional Changes of Wawa-Zange Forest, Gombe, Nigeria
This study aimed to assess the vegetation changes and sustainability of the Wawa-Zange grazing reserve. The study reported the vegetation composition and changes through time (1975-2020) for the entire Wawa-Zange grazing reserve, one of the world's largest grazing reserves. Multi-temporal satellite imageries were acquired from the USGS Earth Explorer collection of Landsat data series and employed in this study. Normalized Difference Vegetation Index (NDVI) technique was used to delineate forest and non-forest areas. ArcMap was used to elucidate the transition of the reserve. The result obtained from the study showed that the reserve has changed, owing to the spread of agricultural boundaries, overgrazing, and deforestation. During the study period, the non-vegetation area expanded from 3.88 percent to 46.74 percent, while the agricultural area increased by 37 percent. This approximately 50 percent decline in vegetation cover indicates a significant decline in β-diversity at large spatial scales. It was observed that by 2030, the reserve could lose 67% of its vegetation cover. To stop land conversion and unsustainable agricultural practices, strict legislative frameworks and regulations should be implemented. Sustainable land management techniques like agroforestry and reforestation should also be encouraged.
Isothermal Modelling of the Adsorption of Malachite Green onto Rice husks
The rice milling process produces rice husks as a by-product. It is one of the most important agricultural leftovers in terms of volume. The data of the sorption isotherm of Malachite Green sorption onto rice husks, which was plotted using linearized plots of isothermal models were reanalyzed using twenty isothermal models using nonlinear regression. Nineteen models — Henry, Langmuir, Freundlich, Jovanovic, Redlich-Peterson, Sips, Toth, Hill, Khan, BET, Vieth-Sladek, Radke-Prausnitz, Fritz-Schlunder III, Unilan, Baudu, Marczewski-Jaroniec, Fritz-Schluender IV, Weber-van Vliet and Fritz-Schluender V – fitted the data best using non-linear regression. Statistical analysis based on error function analyses such as root-mean-square error (RMSE), adjusted coefficient of determination (adjR2), accuracy factor (AF), bias factor (BF), Bayesian Information Criterion (BIC), corrected AICc (Akaike Information Criterion), and Hannan-Quinn Criterion (HQC) showed that the best isotherm model was found to be the Redlich-Petersen with the lowest RMSE and AF, BF and adjR2 values closest to unity and lowest BIC, HQC and AICc values followed (descending order) by Jovanovic, Langmuir, Henry and Freundlich. The maximal adsorption capacity in the Jovanovic model will be used for comparative purposes since the Redlich-Petersen model does not feature a similar parameter. The maximal adsorption capacity expressed in milligrams per gram (mg/g), for the Jovanovic model, denoted by qmJ and Kj-the Jovanovic constant, showed the calculated values of 4.04 mg/L (95% confidence interval; 3.306 to 4.773) and 0.445 (95% confidence interval; 0.264 to 0.627), respectively. The nonlinear regression method provides parameter values within the 95% confidence interval, facilitating improved comparability with prior research.
Copyright (c) 2023 Bulletin of Environmental Science and Sustainable Management (e-ISSN 2716-5353) http://creativecommons.org/licenses/by/4.0
Exploring the Influence of Azo Dye Congo Red on Acinetobacter baumannii YNWH 226 Growth: A Secondary Modeling Study
One of the challenges that face the textile industry is the release of effluents that are not wanted, most notably colors that do not degrade. This is one of the issues that plagues the industry. This is a concern since it affects the environment. Bioremediation using dye-degrading bacterium is appealing as bacterial metabolism converts hazardous dye to harmless carbon dioxide and water as byproducts. In this study, various secondary growth models such as Luong, Yano, Teissier-Edward, Aiba, Haldane, Monod, Han, and Levenspiel were employed. Following thorough statistical analyses such as root-mean-square error (RMSE), adjusted coefficient of determination (adjR2), bias factor (BF), and accuracy factor (AF), the Luong model emerged as the most optimal choice. the half-saturation constant for maximal growth, maximal growth rate and maximal concentration of substrate tolerated and curve parameter that defines the steepness of the growth rate decline from the maximum rate symbolized by Ks, max and Sm, and n were 8.023 mg/L (95% C.I., -153.852 to 169.898), 0.437 per d (95% C.I., -0.121 to 0.995), 551.629 mg/L (95% C.I., 378.823 to 724.435) and 3.907 (95% C.I., -8.808 to 16.621), respectively. These novel constants discovered during the modeling process could serve as valuable inputs for subsequent modeling pursuits.
Substrate Inhibition Kinetics Models for Fitting the Growth Rate of Phenol by an Acclimatized Mixed Bacterial Consortia from an Anaerobic Batch Reactor
Particularly hazardous among the numerous synthetic chemicals made by mankind is phenol. A considerable number of the over 80,000 chemicals manufactured in the United States for industrial purposes are phenol and phenolic compounds, which enter the environment without undergoing sufficient safety evaluation. The potential utilization of phenol as a carbon source by several species of bacteria renders bioremediation of this hazardous substance an auspicious prospect. Our research revealed that the growth rate of acclimatized mixed bacterial consortia from an anaerobic batch reactor was considerably inhibited when exposed to extremely high quantities of phenol. The growth parameter-specific growth rate was determined by employing the modified Gompertz primary growth model. In the present investigation, we extend our previous work by employing multiple substrate inhibition kinetic models—including Monod, Teissier, Haldane, Yano and Koga, Aiba, Han and Levenspiel, Luong, Moser, Webb, and Hinshelwood—to further model the effect of substrate or phenol on the growth rate of the bacterium. All cases exhibit significant fits, with the exception of the Luong and Hinshelwood models. The Haldane model exhibited a higher degree of correspondence with the growth rate data obtained at various concentrations of phenol, as determined by the statistical tests. The designated values of the Haldane constants were maximal reduction rate, half saturation constant for maximal reduction and half inhibition constant which are symbolized by max, Ks and Ki were 0.157 hr-1 (95% confidence interval 0.072 to 0.231), 32.042 mg/L (95% C.I. 14.603 to 49.480) and 234.095 mg/L (95% C.I. 181.83 to 286.17), respectively. The output of curve fitting interpolation should not be considered the true value, and the user should be duly informed of this as the true max should be the point at which the slope's gradient becomes zero; in this instance, the value was 0.095 h-1 at 50.1 mg/L phenol.
Characterization of a Glyphosate-degrading Bacterium from a Paddy Field in Kepala Batas, Penang
Bioremediation of contaminants, including glyphosate, a herbicide, is an economically viable and environmentally friendly technique. Glyphosate is the most utilized herbicides for weed management. Pollution from glyphosate is dangerous to wildlife and their habitats. Soil Pseudomonas sp. strain UMP-KB2 obtained from a paddy field was used as the only source of carbon and described for its capacity to degrade glyphosate. The growth of these bacteria was measured spectrophotometrically as A600 nm in response to changes in incubation time, g inoculum size, glyphosate concentration (carbon source), temperature and pH. The bacterium degrades glyphosate optimally at pH 7.0, glyphosate concentration of 0.5 g/L, temperatures of between 30 and 35 ºC, and inoculum size 1% (v/v). Growth at 0.5 g/L glyphosate shows a two-day lag period and nearly 90% degradation after six days of incubation. The isolation of a glyphosate-degrading bacterium that utilizes glyphosate as a carbon source will be very useful in mineralizing glyphosate in contaminated agriculture soil.
Pseudomonas sp. strain Neni-12 Growth on Acrylamide Exhibit Substrate Inhibition
The bacterium Pseudomonas sp. strain Neni-12 isolated from volcanic soil showed the ability to grow on high concentrations of acrylamide. The acrylamide-degrading bacterium grew best in the presence of glucose with acrylamide as the sole nitrogen source. The inhibitory effects of acrylamide as a substrate for growth of this bacterium on the growth rate was modelled using several secondary models such as Haldane, Monod, Moser, Webb, Teissier (Tessier), Han-Levenspiel, Yano-Koga, Aiba, Luong, Webb and Hinshelwood. The models Luong and Han-Levenspiel failed to fit the data. The statistical analysis and accuracy of the all six kinetic models used indicated that Haldane was the best model with small values for RMSE and AICc, adjusted R2 values, F-test and with Bias Factor and Accuracy Factor nearest to unity (1.0). The Haldane’s constants: maximal growth rate, half-saturation constant for maximal growth and half-inhibition constant symbolized by max, Ks, and n were 1.637 h-1 (95% C.I., 1.297 to 1.978), 210.99 mg/L (95% C.I., 135.01 to 286.97), 5198 mg/L (95% C.I., 4642 to 5755) and 545.68 (95% C.I., 389.94 to 701.43), respectively. The model’s parameter obtained in this study will be very useful in future scale-up macrocosm studies.
Modelling the Inhibitory Effect of Mercury on the Growth Rate of a Bacterium on Acrylamide
Mercury was a potent inhibitor of the acrylamide-degrading Pseudomonas sp. strain DrY Kertih bacterium. The bacterium is capable of growing on acrylamide as a nitrogen source. Growth shows a sigmoidal pattern with lag times of 7–10 hours when exposed to increasing amounts of mercury. Bacterial growth was significantly slowed down while the lag period was increased as the concentration of mercury was increased to 0.1 mg/L, and eventually, growth stopped altogether. Growth rates at various mercury concentrations were calculated using a modified Gompertz model to obtain the maximum specific growth rate parameter. The modified Han-Levenspiel, modified Andrews, Shukor, Kai, Liu, Wang and Amor models were applied to the growth rates. The Amor model was unable to fit the curve. The Wang model performed the best statistically, with the lowest RMSE and AICc, the highest adjusted correlation coefficient (adR2), and AF and BF values closest to unity. The parameters obtained were Kc, max and m which represent critical heavy metal ion concentration (g/l), and maximum growth rate (g/l h) and empirical constant values were KC, max and m which represent inhibition constant (mg/L), maximum growth rate (per h) and empirical constant values were 0.054, 0.431 and 4.295, respectively. The results obtained in this study are useful when remediation works on polluted sites containing acrylamide co-contaminated with metal ions especially mercury.
Isolation and Characterization of a Diesel-degrading Bacterium from Waters Near the Langkawi UNESCO Kilim Karst Geoforest Park
This study explored the biodegradation potential of bacterial isolates from various locations in Malaysia, focusing on their ability to utilize diesel as a carbon source. Among the ten isolates tested, Isolate 4, identified as Pseudomonas sp. strain UPM-Langkawi 3 based on morphological, cultural, and biochemical properties, exhibited significant growth on 2.5% diesel, indicating rapid activation of diesel assimilation mechanisms. Using ABIS online software analysis, the strain was provisionally identified as Pseudomonas sp. UPM-Langkawi 3. Experimental results demonstrated that the optimal conditions for the growth of strain UPM-Langkawi 3 were between 6 and 8 % (v/v) diesel concentration, a temperature of between 28 and 35 °C, and a pH range of between 7.5 to 8.5. The strain showed inhibited growth at higher diesel concentrations and temperatures above 40°C and at a lower pH of 5.7. Among several inorganic nitrogen sources tested, 0.9% w/v ammonium sulphate was found to be the most effective, corroborating previous research. The study underscores the efficacy of Pseudomonas sp. strain UPM-Langkawi 3 in degrading diesel, suggesting its potential use in bioremediation of diesel-contaminated environments. Further research should employ molecular identification techniques, such as 16srRNA gene sequencing, to confirm the species identity and optimize biodegradation conditions. This work establishes a foundation for utilizing indigenous bacterial strains in environmental management strategies, particularly for areas impacted by hydrocarbon pollutants.
Characterization of the Growth of Pseudomonas sp. strain DrY135 on Acetamide
Acetamide is heavily used as a plasticizer and stabilizer and in the methylamine manufacturing process. There has been a modest but steady rise in worldwide interest in microbe-mediated acetamide decomposition or degradation as a bioremediation method. A previously isolated molybdenum-reducing bacterium with amide-degrading capability is characterized for its growth on acetamide in this study. The bacterium growth optimally in between 500 and 1000 mg/L of acetamide, an optimal pH of between 6.5 and 8.0, and optimal temperatures supporting growth of between 30 and 35 °C. Toxic heavy metals, such as mercury, silver and copper slowed down the growth of this bacterium on acetamide. Growth of acetamide exhibits potent inhibition on growth as evidenced from the considerable lag phase that increases as the concentrations of acetamide was increased. As the tolerance level to acetamide for this bacterium is relatively higher than other acetamide-degrading bacteria in the literature, this bacterium can potentially be an excellent acetamide bioremediation agent.
Silver Impact on the Growth Rate of an SDS-degrading Pseudomonas sp. strain Maninjau1 Explored using Predictive Models
The use of silver nanoparticles in fabrics in conjunction with detergent in washing may release silver ions that can inhibit detergent remediation by microorganisms. The SDS-degrading bacterium, Pseudomonas sp. strain Maninjau1, showed prominent inhibition in the presence of silver ion. When exposed to varying silver concentrations, the bacterium's growth followed a sigmoidal pattern, exhibiting lag periods ranging from 2.5 to 5.5 hours, as modeled using the modified Gompertz model. Increasing the silver concentrations progressively slowed bacterial growth, with concentrations as low as 1.0 mg/L halting bacterial growth rate altogether. To assess these effects, the modified Gompertz model was used to determine growth rates across different silver concentrations. The results were then evaluated against several models, including the modified Han-Levenspiel, Wang, Liu, Shukor, modified Andrews, and Amor models. The Amor model did not adequately fit the growth curves. Statistical analysis revealed that the modified Han-Levenspiel model performed best, as indicated by the lowest RMSE and AICc values, the highest adjusted correlation coefficient (adR2), and AF and BF values closest to unity. The Liu, Shukor, modified Andrews, and Wang models followed in descending order of performance. The parameters obtained from the modified Han-Levenspiel model, which are max (h-1) and Ccrit (mg L-1) and m which represent maximum growth rate, critical heavy metal ion concentration and empirical constant values were 0.196, 1.1134 and 0.632, respectively. The modified Han-Levenspiel model effectively predicts the critical concentrations of heavy metals that can completely inhibit bacterial growth. This robust modeling approach highlights the model's suitability for forecasting the impact of silver on the growth dynamics of Pseudomonas sp. strain Maninjau1, particularly under conditions of toxic stress.
The Effect of Temperature on the Specific Growth Rate of Bacillus circulans strain Neni-10 on Metanil Yellow: Determination of Activation energy, Temperature Coefficient and Q10 Value
bioremediation process, analyzing the effect of temperature to the specific growth values of a remediating microbes on a particular xenobiotic will yield important information that can be translated into the field in future studies. Due to their tiny size, microbes are particularly very sensitive to variations in temperature. Temperature typically influences the growth and metabolic activity of bacterium on the substrates they are grown upon. There are several models that may be utilized to mimic the rate of growth of microbes on a numerous plethora of substrate or media at varying temperatures. Among the most often adopted models is the Arrhenius model, in part because to its minimal parameter number. To study the effect of temperature on Bacillus circulans strain Neni-10 growth on Metanil Yellow, a chevron-like graph with a discontinuous apparent activation energy was observed. The graph's exhibited a breakpoint at 31.91 °C. Per the regression analysis obtained, the activation energy needed for growth on Metanil Yellow at temperatures ranging between 20 and 30 °C was 62.07 kJ/mol. At temperatures ranging from 35 to 45 °C, its activation energy reduces to 30.93 kJ/mol. At a temperature of 35 °C, the maximum growth rate of the bacterium on Metanil Yellow occurred, and this rate was found to be reduced as the temperature was increased.
Mathematical Modelling on the effect of Mercury on the Growth Rate of Serratia marcescens strain DRY6 on Sodium Dodecyl Sulphate
Sodium dodecyl sulfate (SDS) or sodium lauryl sulfate (SLS) is a common anionic surfactant found in various cleaning and personal hygiene products. It has both a polar "headgroup" and a hydrocarbon tail, giving it amphiphilic properties that make it effective as a detergent. However, this also makes it a major pollutant in aquatic environments. Researchers have studied the biodegradation of SDS by microorganisms, particularly bacteria, as a potential cleanup method. It has been found that mercury can significantly inhibit the degradation of SDS by the Serratia marcescens strain DRY6 bacteria. At different mercury concentrations, the bacteria exhibited sigmoidal growth with lag times of 7 to 10 hours, but overall growth was decreased with higher mercury concentrations, with a concentration of 1.0 g/L virtually stopping all growth. A modified Gompertz model was used to calculate growth rates at various mercury concentrations, and these rates were then modeled using five different models: modified Han-Levenspiel, Wang, Liu, modified Andrews, and Amor. Only three of the models (Wang, modified Han-Levenspiel, and Liu) were able to accurately fit the curve, with the Wang model performing the best statistically. The Wang model yielded estimates of 0.216 (95% confidence interval: 0.193 to 0.239) for the critical heavy metal ion concentration, 1.05 (95% confidence interval: 0.938 to 1.167) for the maximum growth rate, and 0.389 (95% confidence interval: 0.148 to 0.636) for the empirical constant , represented by Ccrit, max and m, respectively.
Copyright (c) 2022 Bulletin of Environmental Science and Sustainable Management (e-ISSN 2716-5353) http://creativecommons.org/licenses/by/4.0
Isolation and Characterization of a Molybdenum-reducing Enterobacter aerogenes strain Amr-18 in Soils from Egypt that Could Grow on Amides
In the foreseeable future, bioremediation is by far the most cost-effective method for removing noxious chemical toxins and organic contaminants, especially at low concentrations when other methods like physical or chemical procedures wouldn't be successful. For the objective of bioremediation, we have isolated a molybdenum-reducing bacteria from agricultural soil. The ideal pH and temperature ranges for the bacterium to reduce molybdate to molybdenum blue (Mo-blue) are 6.3 and 6.8, respectively. The best electron donor for molybdate reduction was glucose, which was followed in descending order by sucrose, lactose, l-rhamnose, d-mannose, raffinose, d-adonitol, maltose, d-mannitol, melibiose, cellobiose, glycerol, and d-sorbitol. Phosphate concentrations of 7.5 mM and molybdate concentrations of 15 – 20 mM are also necessary. The Mo-blue that was formed had an absorption spectrum that was comparable to that of earlier Mo-reducing bacteria and closely resembled that of reduced phosphomolybdate. At 2 ppm, copper (II), mercury (I), and silver I hindered molybdenum reduction by 80.2, 74.8, and 30.4%, respectively. The bacterium was tentatively identified as Enterobacter aerogenes strain Amr-18 after phenotypic and biochemical identifications. The bacterium could thrive on the amides, acrylamide, acetamide, and propionamide and could use acrylamide as an electron donor for molybdenum reduction. This bacterium has a highly valued trait that makes it useful for bioremediation: the capacity to detoxify a variety of toxicants.
Screening of Chromium-reducing Bacteria from Tannery Effluents
Tannery effluent has remained one of the major sources of chromium pollution in the environment. Although conventional methods have been widely used, they are inefficient and costly. Bacterial remediation is one of the best alternatives being proposed. Therefore, the aim of this research was to isolate bacteria from tannery effluents and screen them for chromium-reduction potentials. Three different tannery effluents were collected and used for the isolation of chromium-reducing bacteria. The organisms were identified using morphological and biochemical characteristics and screened on 1% (v/v) Cr (VI). The results revealed the presence of three bacterial species, namely: Bacillus subtilis, Escherichia coli and Pseudomonas sp. The screening results revealed that out of the three bacterial isolates, Bacillus subtilis had the highest reduction potential (86.23%), while equal reduction capacity was recorded in both E. coli and Pseudomonas sp. (84.03%). Therefore, these three isolates can be used as a consortium to improve biological remediation of Cr (VI) effluents.
Response Surface Method for the Optimization of Pseudomonas sp. strain DrY135 Growth on Acrylamide as a Nitrogen Source
Acrylamide pollution and contamination can come from a variety of sources and is an emerging toxic pollutant that need remediation. A molybdenum-reducing bacteria that had been previously isolated and demonstrated the ability to degrade amides was further studied of its critical parameters contributing to optimum growth on acrylamide. The Box-Behnken design was utilized in optimizing the three previously identified significant components (pH, incubation time and acrylamide concentration). ANOVA, the pertubation's plot, and several other diagnostic plots were utilized in the analysis of the significant factors or parameters that contributed. The model was supported by the diagnostic plots including the half-normal, Cook's distance, leverage vs runs, residual vs runs, Box-Cox, DFFITS, and DFBETAS. Conditions that were predicted to be optimal were found and analyzed in order to find the optimal growth given the factors that were used and to determine the optimal concentration, which was 1 g/L. The solutions for finding the optimal growth predicted a growth maximum of 12.055 Log CFU/mL (95 percent confidence interval (C.I.) from 11.550 to 12.593), and verification using experimental results resulted in a growth of 12.908 Log CFU/mL (12.744 to 13.072) with the results being close to the predicted values but was significantly higher than the predicted data. The second numerical optimization was for predicting the highest acrylamide concentration tolerable for growth and the solution shows a predicted a growth maximum of 12.055 Log CFU/mL (95 percent confidence interval from 11.550 to 12.593). This solution was experimentally verified resulting in a growth of 12.195 Log CFU/mL (95 percent confidence interval from 11.806 to 12.584) with the actual results being in accordance with the predicted values. The results of the RSM exercise showed that growth on acrylamide may be optimized more effectively with RSM than with OFAT, which indicates that RSM is more useful than OFAT in this regard.
A Two-Level Factorial Design for Screening Factors that Influence the Growth of E. cloacae strain UPM2021a on Acrylamide
The world has gradually but steadily paid more attention to the use of bacteria to break down acrylamide as a bioremediation technique. Using a two-level factorial design, a previously obtained molybdenum-reducing bacterium with the ability to degrade amides was further identified on important factors influencing its optimal development on acrylamide. In order to screen five distinct parameters impacting the development of the bacterium on acrylamide, a two-level factorial design was used. Three center point replications were used in a total of 32 tests. These variables include pH, temperature, the length of the incubation period, the concentrations of acrylamide and glucose. Acrylamide concentration, pH, and incubation time were found to be key factors in this bacterium's growth on acrylamide by the two-factor factorial design and were successfully adjusted using RSM in subsequent studies. Using ANOVA, Pareto's chart, pertubation's plot, and other diagnostic plots, the significant contributing components or parameters were analyzed. The two-level factorial conclusion was supported by diagnostic plots including half-normal, Cook's distance, residual vs runs, leverage vs runs, Box-Cox, DFFITS, and DFBETAS. The acrylamide range used in this investigation is well within the range that most acrylamide-degrading bacteria have been found to tolerate. Longer incubation times allow for higher growth, and many acrylamide-degrading microorganisms have been observed to have incubation times of two to five days for optimized growth. The majority of acrylamide-degrading microorganisms thrive at circumstances that are close to neutral, and the findings of this study are consistent with published literature trends in this regard.