Microbial biodegradation

About: Microbial biodegradation is a research topic. Over the lifetime, 1647 publications have been published within this topic receiving 75473 citations.

Microbial degradation of phenol by activated sludge in a batch reactor

Abstract: Biodegradation of phenol in a batch reactor was investigated using activated sludge. The sludge was able to degrade phenol of initial concentrations up to 1.500 mg/dm. The optimum temperature and pH for the reaction were determined in extensive tests. The optimum pH was around 6, whereas the temperature showed no significant impact on the biodegradation rates over the investigated conditions. This activated sludge degraded phenol at the maximum rate of 0.048 g phenol/(g VSS·h) at pH 6 and 30 °C, whereas inhibitory effects existed at concentrations higher than 100 mg/dm. The Haldane kinetic model was used to elucidate the kinetics of phenol degradation in an activated sludge. The kinetic parameters were estimated to be qmax = 0.4695 g phenol/(g VSS·h), KI = 28.4860 mg/dm, and KS = 603.9869 mg/dm, with the correlation coefficient (R) of 0.9599. The high qmax value for phenol biodegradation shows that the activated sludge exhibited high resistance to phenol.

Biodegradation of Epoxy and MF Modified Polyurethane Films Derived from a Sustainable Resource

Abstract: Mesua ferrea L. seed oil (MFLSO) modified polyurethanes blends with epoxy and melamine formaldehyde (MF) resins have been studied for biodegradation with two techniques, namely microbial degradation (broth culture technique) and natural soil burial degradation. In the former technique, rate of increase in bacterial growth in polymer matrix was monitored for 12 days via a visible spectrophotometer at the wavelength of 600 nm using McFarland turbidity as the standard. The soil burial method was performed using three different soils under ambient conditions over a period of 6 months to correlate with natural degradation. Microorganism attack after the soil burial biodegradation of 180 days was realized by the measurement of loss of weight and mechanical properties. Biodegradation of the films was also evidenced by SEM, TGA and FTIR spectroscopic studies. The loss in intensity of the bands at ca. 1735 cm−1 and ca. 1050 cm−1 for ester linkages indicates biodegradation of the blends through degradation of ester group. Both microbial and soil burial studies showed polyurethane/epoxy blends to be more biodegradable than polyurethane/MF blends. Further almost one step degradation in TG analysis suggests degradation for both the blends to occur by breakage of ester links. The biodegradation of the blends were further confirmed by SEM analyses. The study reveals that the modified MFLSO based polyurethane blends deserve the potential to be applicable as “green binders” for polymer composite and surface coating applications.

Microbial Biodegradation of 2,4,5-Trichlorophenoxyacetic Acid and Chlorophenols

Abstract: Maintaining the carbon, nitrogen, and sulfur balances in the environment is one of the main tasks of microorganisms in nature; microorganisms degrade most compounds so that their basic elements can be recycled. However, naturally occurring chlorinated hydrocarbons are rather rare (25). Chlorinated synthetic chemicals such as PCBs, dichloro-diphenyl-trichloro-ethane (DDT), and 2,4,5-T, generally are degraded only slowly (20,23,24), mostly through co-oxida-tive metabolism (1,23), The persistence of these compounds is thought to be due to a lack of the ability of microbial cells to derive their energy and cellular constituents from the oxidative metabolism of these compounds (1), Persistence of chemicals in nature will amplify our pollution problems as time progresses, so that even what seems like an insignificant amount of a given chemical, if applied repeatedly, will accumulate until its environmental impact is felt.

Isolation and characterization of phenol degrading bacteria from oil contaminated soil

Abstract: Microorganisms plays a major role for saving our environments by degrading xenobiotic compounds chemicals wastes, which are toxic either in their native form or modified to be toxic. Isolation of microbial strain able to degrade chemical compounds was started usually from polluted sources, such as soil. In present study, aerobic bacteria isolated from soil contaminated with industrial xenobiotic compounds using enrichment technique containing phenol as sole source of carbon and energy was isolated in pure culture and selected for their ability to degrade phenol. The soil bacterium was identified as Streptococcus epidermis coded as (OCS-B). The selected microbial strain was able to degrade phenol up to 200mg/l which was also confirmed by HPLC analysis and so can be effectively used for bioremediation of phenol contaminated sites. Degradation intermediate compounds were also determined. Outcome of this study offer a useful guideline in evaluating potential phenol degraders from the environment.