Microbial Profiling of Malera and Phab: Starters Used for Preparing Traditional Fermented Foods and Beverages in Himachal Pradesh, India

Background: Traditional fermented food preparation uses customary processing methods passed on from generation to generation under natural conditions. These fermented foods use native flora without being aware of the significant role of microbes involved in the fermentation process. Therefore, the present study aimed to determine the bacterial composition of traditional starters used in different fermented food preparations in Himachal Pradesh region India. Methods: The study investigated the bacterial DGGE (Denaturating Gradient Gel Electrophoresis) profile targeting V3 region of 16S rRNA of two traditional starters known as Malera and Phab. The starters are used in the preparation of fermented cereals product known as bhaturoo and alcoholic beverages. The Shannon diversity and richness were calculated from DGGE profile. The 16S rRNA gene sequences of identified bacterial species were deposited in NCBI database. Results: The DGGE profile identified eleven and seven different bacterial strains in Malera and Phab, respectively. The Shannon diversity index of 1.07 and 0.94 was obtained for Malera and Phab, respectively. The bacterial population was dominated by different strains of Bifidobacterium sp. in both the starters along with the presence of non lactic enterobacteriacae members such as Klebsiella sp. and a pathogenic strain of Dickeya chrysanthemi. Conclusion: The study is the first report on microbial profiling of microflora of starters. A careful examination of individual components and method of preparation of the starters should be taken to avoid contamination by pathogens.

Molecular Diversity Assessment of Plant Growth Promoting Rhizobacteria Using Denaturing Gradient Gel Electrophoresis (DGGE) of 16s rRNA Gene

The rhizobacteria were isolated from rhizosphere of rice plant of different fields of 4 districts of Nepal and 5 districts of Bihar and Uttar Pradesh, adjoining states of India with Nepal. The DGGE analysis was performed for diversity analysis. For the construction of dendrogram, 16S rRNA gene was amplified by two different sets of primers. The DGGE ladder consisting of PCR amplified products of nine pure bacterial cultures were obtained. The first DGGE ladder was prepared by 400 bp fragment of 16S rDNA with GC clamp and the second DGGE ladder was prepared with 200 bp fragment of 16S rDNA with GC clamp. The perpendicular DGGE of these amplicons based on their melting behavior clearly demonstrated separation of different isolates. The 16S rDNA fragment amplified with primer set of V2-V3 regions with GC clamp showed separation between 40-60% of denaturant. The DGGE profile based on primer set F352T and 519r for various bacteria present in soil samples of 5 districts of India and 4 districts of Nepal revealed that the number of bands which might be specific for diazotrophic isolates varied from 2 to 11. The dendrogram constructed based on DGGE profile of various samples of 5 districts of India and 4 districts of Nepal showed that all the samples could be clustered in nine groups with 58-96% similarity to each other. Among all these 37 samples, only Var-4 and Var-5 showed 100% similarity, no other samples from any site showed 100% similarity. Int. J. Appl. Sci. Biotechnol. Vol 5(1): 72-80

Effect of oxytetracycline on performance and microbial community of an anoxic–aerobic sequencing batch reactor treating mariculture wastewater

The DGGE profile illustrates that the microbial communities of activated sludge exhibit obvious variations under OTC stress.

Microbial Communities Involved in Anaerobic Degradation of Unsaturated or Saturated Long-Chain Fatty Acids

ABSTRACTAnaerobic long-chain fatty acid (LCFA)-degrading bacteria were identified by combining selective enrichment studies with molecular approaches. Two distinct enrichment cultures growing on unsaturated and saturated LCFAs were obtained by successive transfers in medium containing oleate and palmitate, respectively, as the sole carbon and energy sources. Changes in the microbial composition during enrichment were analyzed by denaturing gradient gel electrophoresis (DGGE) profiling of PCR-amplified 16S rRNA gene fragments. Prominent DGGE bands of the enrichment cultures were identified by 16S rRNA gene sequencing. A significant part of the retrieved 16S rRNA gene sequences was most similar to those of uncultured bacteria. Bacteria corresponding to predominant DGGE bands in oleate and palmitate enrichment cultures clustered with fatty acid-oxidizing bacteria withinSyntrophomonadaceaeandSyntrophobacteraceaefamilies. A low methane yield, corresponding to 9 to 18% of the theoretical value, was observed in the oleate enrichment, and acetate, produced according to the expected stoichiometry, was not further converted to methane. In the palmitate enrichment culture, the acetate produced was completely mineralized and a methane yield of 48 to 70% was achieved from palmitate degradation. Furthermore, the oleate enrichment culture was able to use palmitate without detectable changes in the DGGE profile. However, the palmitate-specialized consortia degraded oleate only after a lag phase of 3 months, after which the DGGE profile had changed. Two predominant bands appeared, and sequence analysis showed affiliation with theSyntrophomonasgenus. These bands were also present in the oleate enrichment culture, suggesting that these bacteria are directly involved in oleate degradation, emphasizing possible differences between the degradation of unsaturated and saturated LCFAs.