Microbial biodegradation

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

Degradation of hazardous organic compounds by rhizosphere microbial communities

Abstract: Publisher Summary The variety of plants and chemicals studied for the evidence of microbial degradation in the rhizosphere strongly suggests that a diverse and synergistic microbial community, rather than a single species, is responsible for biotransformation of toxicants in the rhizosphere. Participation of a microbial community is implicated by (i) the extreme diversity and complexity of toxicants degraded, and (ii) the knowledge that many of these compounds are completely degraded only in the presence of interacting microbial populations (consortia). Moreover, data presented, herein, from phospholipid fatty acid analysis, 14C acetate incorporation, and PHA analysis of micro-organisms from the rhizosphere are consistent with the participation of a microbial community in TCE degradation. Other mechanisms can also be invoked to explain how microbial transformations occur in the rhizosphere. Collectively, these factors have important implications for the successful use of vegetation to increase the participation of micro-organisms in biotransformation of toxicants at hazardous waste sites.

Bioremediation of compounds hazardous to health and the environment: An overview

Abstract: Publisher Summary This chapter focuses on the fundamental microbial mechanisms (oxidative, reductive, and hydrolytic reactions) and associations in plant and microbial populations (competition, cross-feeding and commensalism), which may be essential to their success. Bioremediation of the chemicals in the soil depends on the activities of microbes in the soil, or in association with the root system. Chemical/physical properties of the chemical itself can influence the availability of the chemical to the microbe, or the susceptibility to degradative processes. Molecular alterations catalyzed by the microbial processes include oxidation, reduction, hydrolysis, de-esterification, dehalogenation, dealkylation, conjugation, and others. These processes usually result in a non-toxic chemical in the case of a pesticide, or in decreasing contamination levels of hazardous materials. Dissipation of pesticides in the soil involves several processes: volatilization, photodecomposition, leaching, adsorption, and microbial degradation. This chapter has been an overview of bioremediation processes, together with a few examples to illustrate the principles and efficacy of those processes.

Methanogenic degradation of branched alkanes in enrichment cultures of production water from a high-temperature petroleum reservoir.

Abstract: Branched alkanes are important constituents of crude oil and are usually regarded as resistant to microbial degradation, resulting in little knowledge of biochemical processes involved in anaerobic branched alkanes biodegradation. Here, we initiated an incubation study by amendment of iso-C9 (2-methyl, 3-methyl, and 4-methyloctane) as substrates for methanogenic degradation in production water from a high-temperature petroleum reservoir. Over an incubation period of 367 days, significant methanogenesis was observed in samples amended with these branched alkanes. The strong methanogenic activity only observed in iso-C9 amendments suggested the presence of microbial transformation from iso-alkanes into methane. GC-MS-based examination of the original production water identified an intermediate tentatively to be iso-C9-like alkylsuccinate, but was not detected in the enrichment cultures, combined with the successful amplification of assA functional gene in inoculating samples, revealing the ability of anaerobic biodegradation of iso-C9 via fumarate addition pathway. Microorganisms affiliated with members of the Firmicutes, Synergistetes, and methanogens of genus Methanothermobacter spp. were highly enriched in samples amended with iso-C9. The co-occurrence of known syntrophic acetate oxidizers Thermoacetogenium spp. and Methanothermobacter spp. (known hydrogenotrophic methanogens) indicates a potential syntrophic acetate oxidation associated with the methanogenic biodegradation of iso-C9. These results provide some useful information on the potential biodegradation of branched alkanes via methanogenesis and also suggest that branched alkanes are likely activated via fumarate addition in high-temperature petroleum reservoirs.

Phenol biodegradation by bacterial strain O-CH1 isolated from seashore.

Abstract: phenol and phenolic compounds are among the most recognized environmental pollutants which exist in industrial wastewater and enter the biological cycles due to the solubility in water. Bioremediation is one of the cost-effective and Eco-friendly methods for phenol removal. In this study, the most effective phenol-degrading bacterial strain was isolated and identified from the shores of the Oman Sea by 16S rDNA. The optimal conditions of various factors, such as pH, temperature, carbon to nitrogen ratio and salinity for the phenol biodegradation, were determined using the experimental design based on Taguchi method with L9 array (34). Ability of the isolated strain (Halomonas elongata strain O-CH1) in degradation of different phenol concentrations was analyzed. The optimum operating conditions for phenol removal were determined in pH value of 8, temperature of 35 ˚C, carbon to nitrogen ratio of 100:30 (g/L) and salinity of 35 (g/L). In these conditions, 97% of the phenol was removed from the mediums. According to the optimization results, salinity and pH were the most influential factors in the biodegradation of phenol. The O-CH1 was able to grow and degrade phenol at concentrations of 250 mg/L to 1500 mg/L. Considering the high potential of this strain for phenol degradation, determining the optimal conditions for the biodegradation and its efficacy at high concentrations of phenol, the findings in this study can be used in the biological treatment of phenolic wastewater.