Pu-erh is a tea produced in Yunnan, China by microbial fermentation of fresh Camellia sinensis leaves by two processes, the traditional raw fermentation and the faster, ripened fermentation. We characterized fungal and bacterial communities in leaves and both Pu-erhs by high-throughput, rDNA-amplicon sequencing and we characterized the profile of bioactive extrolite mycotoxins in Pu-erh teas by quantitative liquid chromatography-tandem mass spectrometry. We identified 390 fungal and 629 bacterial OTUs from leaves and both Pu-erhs. Major findings are: 1) fungal diversity drops and bacterial diversity rises due to raw or ripened fermentation, 2) fungal and bacterial community composition changes significantly between fresh leaves and both raw and ripened Pu-erh, 3) aging causes significant changes in the microbial community of raw, but not ripened, Pu-erh, and, 4) ripened and well-aged raw Pu-erh have similar microbial communities that are distinct from those of young, raw Ph-erh tea. Twenty-five toxic metabolites, mainly of fungal origin, were detected, with patulin and asperglaucide dominating and at levels supporting the Chinese custom of discarding the first preparation of Pu-erh and using the wet tea to then brew a pot for consumption.
Rhizodegradation is one of the best methods for the effective removal of dangerous polycyclic aromatic hydrocarbons pollutants from soil. This is operative due to the high persistent, non-bioavailability nature of PAHs and combined, sequential reactions of bacteria present in rhizosphere of plants. We have conducted pot-culture method to study the degradation of three PAHs compounds namely phenanthrene, anthracene and pyrene in artificially contaminated soils of rhizosphere and non-rhizosphere soil treatments of blackgram(Vignamungo L.) that augmented by two potential PAHs degraders namely Bacillus cereus CPOU13 and Bacillus subtilis SPC14 isolated from naturally contaminated soils for 90days. HPLC studies revealed that degradation percentages of the three PAHs in treatments were more where selected strains augmented to the soil treatments over the non-augmented soils. The rhizosphere treatments that have augmented strains recorded more degradation percentages of phenanthrene, anthracene and pyrene over the rhizosphere treatments that were non-augmented. Pyrene, a high molecular weight PAHs degraded maximum to 96.24% in rhizosphere soil treatment that is augmented with the strains while moderate degradation of pyrene recorded in non-autoclaved soil treatments that contain natural microbial communities. The study of counting of bacterial populations during the experimental period revealed that the populations of the selected and other natural bacteria were gradually increased from the first day, reached maximum by 60days and became almost consistent in 90days in all the treatments. It was also observed that the populations of bacteria were high in rhizosphere treatments compared to the non-rhizosphere soil treatments. With these results it has been predicted that degradation of PAHs in rhizosphere soil treatments is closely associated with the increasing PAHs degrading bacterial populations of selected bacterial strains that may consume more quantity of PAHs for their metabolic activities in rhizosphere soils. Key words: Rhizodegradation, PAHs, HPLC, pot culture.
Biodegradation of polycyclic aromatic hydrocarbons (PAHs) with suitable bacterial strains conveys much interest in recent years. We studied biodegradation of PAHs namely phenanthrene, anthracene and pyrene using two efficient PAHs degrading strains, B. cereus CPOU13 and B. subtilis SPC14 in vitro experiments. Standard HPLC chromatograms for phenanthrene, anthracene and pyrene were plotted separately based on HPLC peak area values and Retension time of known concentrations of the test PAHs and using software, ‘Origin 6.0’. Biodegradation of PAHs mixture containing phenanthrene, anthracene and pyrene was studied in for 13 days. We found that the combination of bacterial strains, B. cereus CPOU13 and B. subtilis SPC14 degraded high amounts of phenanthrene, anthracene and pyrene in 13 days of incubation. The recorded degradation percentages of phenanthrene, anthracene and pyrene were 85.31, 92.82 and 85.70 respectively. Concentration of phenanthrene was degraded from 217µg/5ml to 31.9µg/5ml. Concentration of anthracene was degraded from 211µg/5ml to 16µg/5ml. Concentration of pyrene was degraded from 233µg/5ml to 33µg/5ml in 13 days of incubation. We also observed biodegradation of phenanthrene, anthracene and pyrene from 1st day to 13th day.
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