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Role of Indigenous Microbial Community in Bioremediation
Published in Vineet Kumar, Vinod Kumar Garg, Sunil Kumar, Jayanta Kumar Biswas, Omics for Environmental Engineering and Microbiology Systems, 2023
Bhupendra Pushkar, Pooja Sevak
Betaproteobacteria class of bacteria is highly abundant in organic waste treatment. Another class present in abundance is Rhodocyclales, mainly of genera Azonexus, Azoarcus, Zoogloea, and an unclassified genus that belongs to the family Rhodocyclaceae. The phylum Cloacimonetes is also prominent in the anaerobic organic treatment process. Archaeal methanogenic genera, namely Methanothrix, Methanomethylovorans, Methanoculleus, Methanolinea, and Methanospirillum, are helpful in biological oxygen demand (BOD) reduction (Wang et al., 2018). The nitrogen waste is reported to majorly consist of Proteobacteria, Firmicutes, Bacteroidetes, and Gemmatimonadetes. Alphaproteobacteria and Gammaproteobacteria are predominate groups of Proteobacteria in the nitrogen-containing waste. Other native microbes, namely Dokdonella, Comamonas, and Pseudoxanthomonas of activated sludge, are very much efficient in removing pollutants (Zhang et al., 2021). Proteobacteria and Euryarchaeota together covered 80% and are among the major bacterial and archaebacterial phyla in oil-contaminated sites (Sarkar et al., 2016). Deltaproteobacteria are anaerobes, sulphate reducers, and hydrocarbon degraders, mostly found in the native sample and highly present in hydrocarbon-polluted sites. The sludge community is dominated by the Proteobacteria, but with the addition of hydrocarbon, and other groups such as Alcaligenaceae and Comamonadaceae of Betaproteobacteria are also found in increased number. Chloroflexi increases drastically in the presence of hydrocarbon. Chloroflexi and Deltaproteobacteria degrade alkanes and other hydrocarbons by fermentative-anaerobic metabolism under anaerobic sulphate-reducing conditions and are connected to methanogenesis via reverse electron transport (Roy et al., 2018).
Enhanced anaerobic degradation of quinoline and indole with the coupling of sodium citrate and polyurethane
Published in Environmental Technology, 2021
Jingxin Shi, Wenping Huang, Chunyan Xu, Yuxing Han, Hongjun Han
At class level (Figure 3(b)), the leading classes contained Betaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, Bacteroidia, and Anaerolineae. The percentages of class Betaproteobacteria in R1, R2, R3, and R4 were 1.94%, 1.81%, 33.67%, and 54.49%, respectively. The data showed that class Betaproteobacteria occupied a small proportion in R1 and R2, but a large concentration in R3 and R4. In R4, Betaproteobacteria became the most dominant class. Betaproteobacteria consist of many aerobic or facultative bacteria, whose ability of degradation is variable. Many species of Betaproteobacteria can be found in environmental samples, such as wastewater or soil [23]. Martin et al. [24] have proven that Betaproteobacteria had the ability in degrading the phenanthrene and became the most dominant class in a PAH-contaminated soil. In the study, the PU carrier was beneficial to the enrichment of Betaproteobacteria, and the enrichment of Betaproteobacteria may have some relationships with the degradation of NHCs. The proportions of Gammaproteobacteria in R1, R2, R3, and R4 were 15.67%, 2.42%, 24.2%, and 3.64%, respectively. It was interesting that the PU carrier enriched the Gammaproteobacteria (R3) while the addition of sodium citrate caused a dramatic reduction in Gammaproteobacteria. Some studies have proven that Gammaproteobacteria had potential in the degradation of micro-pollutants in wastewater treatment [25,26]. Figure 3(b) also showed that Deltaproteobacteria, Bacteroidia, and Anaerolineae occupied higher percents in anaerobic sludge reactors (R1 and R2) than that in anaerobic biofilm reactors (R3 and R4), which indicated that PU carrier was not conducive to the enrichment of these bacteria.