Characterisation of an Acrylamide-Degrading Bacterium and Its Degradation Pathway

Abstract

Widespread use of acrylamide by the industry led to the environmental pollution that results from the indiscriminate discharge of acrylamide. The presence of acrylamide in the environment is a major threat due to its neurotoxic, carcinogenic and teratogenic properties. In this work bacterial isolate identified as Burkholderia sp. strain AQ5-13 is capable of degrading acrylamide as both its carbon and nitrogen sources were screen based on the capability of the bacteria to grow on solid basal salt media that contain 500 mg/L acrylamide as sole carbon and nitrogen sources without supplementation of additional carbon or nitrogen sources. Bacteria grow curve study was carried out by measuring the absorbance value at 600 nm. Burkholderia sp. strain AQ5-13 showed a complete life cycle in five days of incubation with no lag phase identified at the earlier growth phase. Optimum conditions for acrylamide degradation was conducted at different initial pH and incubation temperature. Growth optimisation of the bacteria was measured by plate counting in CFU after 48 h of incubation in 250 mL basal salt media that contain 500 mg/L acrylamide. Burkholderia sp. strain AQ5-13 showed optimum growth in acidic media at pH 5.7 (5.57 log 10 CFU/mL) and optimum growth at 30°C (6.84 log 10 CFU/mL) compared to other temperature ranges. Quantitative monitoring of acrylamide degradation was performed using HPLC. Burkholderia sp. strain AQ5-13 could degrade 14% of 500 mg/L acrylamide as its carbon and nitrogen sources after 72 h of incubation at 5 min of retention time. The appearance of acrylic acid peak as an intermediate was not detected, possibly because all the acrylic acid produced had been consumed immediately by the bacterium. The result from this study showed that bacteria Burkholderia sp. strain AQ5-13 has a good potential that can be applied in the bioremediation of waste containing acrylamide.