| Wastewater treatment are facing more and more challenge with the development ofindustry. In the current situation, the biological treatment process should be a priority tothe adoption of wastewater treatment technologies. Among them, anaerobic treatmentprocess to receive more and more attention in recent years. Anaerobic granular sludgetechnology has been widely studied and applied. At present，the highly efficient anaerobicreactor depends on the highly active anaerobic granular sludge with appropriateenvironment. Anaerobic granular sludge constitute of Eubacteria and Archaea. Thefeatures and functions of anaerobic granular sludge are determined by the compositionand function of microbe community.Eubacteria and Archaea community mentioned above in anaerobic granular sludgesamples from full-scale UASB bioreactors treating VB12and avermactin starchwastewater were investigated by PCR-DGGE and by using the technologies ofconstruction of16S rDNA gene clone libraries analysis. The diversity of communitystructure of the microbe, the phylogenetic relationship and the relative abundance inanaerobic granular sludge were discussed and analyzed. The results were shown asfollows.The aim of this study was to investigate methanogenic community of anaerobicgranular sludge samples in anaerobic reactors treating industrial avermectin and VB12fermentation wastewater. The band patterns obtained by DGGE after16S rRNA geneamplification using specific primers for Archaea270showed different band number,optical intensity and distribution between two sludge samples. The diversity indices ofanaerobic community calculated from DGGE band patterns.There was obvious differencein these diversity including Shannon diversity index, Margalef richness index andBerger-Parker dominance index between the both of anaerobic granular sludgesamples.The Archaea community of sludge sample treating VB12wastewater showedhigher diversity and dominance, compared to avermactin sludge sample. The possiblereason for such a result was that different characteristics of two kinds of industrialwastewater, probably such as their different components and stress environment, wouldinfluence Archaea community. The avermectin residual might be responsible for lowerdiversity and dominance of Archaea community. The bands separated by DGGE for archaea were excised, and the DNA was eluted,PCR amplified and sequenced. The sequences were compared with those found in theNCBI database by using BLAST to determine the dominant archaea populations in bothsludge samples.The results of sequencing revealed that these dominant archaeapopulations all belonged to methanogenic archaea. There was distinct predominance ofMethanosarcina in the granular sludge treating VB12wastewater.The Methanosaeta andMethanomethylovorans belonged to Methanosarcina were the dominant species.Inaddition, it was found that Methanosaeta sp. as the main dominant methanogenicpopulation in both sludge samples, indicating the key role of Methanosaeta sp. in thefunction of granular sludge. The phylogenetic analysis of dominant archaea populationsshow that Methanobacteriales and Methanosarcinales were determined to be the mainorders of methanogenic populations in anaerobic granular sludge sample treatingavermectin wastewater. The relative abundances of Methanobacteriales were larger thanthese of Methanosarcinales.The bacterial diversity in anaerobic granular sludge sample treating avermectinwastewater was studied by the16S rDNA cloning and sequencing method with the primer433.63clones were randomly selected, and corresponding partial16S rDNA gene wassequenced and blasted. The results indicated that the bacterial community in the aerobicgranular sludge treating avermectin wastewater was highly diverse, and could be dividedinto seven major groups.The largest fractions were Actinobacteria and Firmicutes, whichaccounted for37.73%and26.42%of the total clones, respectively. The portions ofdeltaproteobacterium, Chloroflexi and Acidobacteria were7.55%,7.55%and5.66%,respectively. The relatively lower portions were3.77%Bacteroides and Synergistetes.Using16S rDNA clone library method with primer archaea G660, the archaeacomposition of the anaerobic granular sludge sample treating VB12wastewater wereinvestigated. The results of sequencing revealed that these dominant archaea populationsall belonged to methanogenic archaea. There was distinct predominance of Methanosaeta(belonged to Methanosarcina) in the.granular sludge treating VB12wastewater. Inaddition, contain a small number of Methanomicrobiales and Methanobacteriales. Theresults were no difference between PCR-DGGE and clone.Relationship between the rate of methane production and the community structure isdiscussed and analyzed. |
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