No abstract

Pe poke is a naturally fermented sticky soybean food of Myanmar. The present study was aimed to profile the whole microbial community structure and their predictive gene functionality of pe poke samples prepared in different fermentation periods viz. 3 day (3ds), 4 days (4ds), 5 days (5ds) and sun-dried sample (Sds). The pH of samples was 7.6 to 8.7, microbial load was 2.1–3.9 x 108 cfu/g with dynamic viscosity of 4.0±1.0 to 8.0±1.0cP. Metataxonomic profile of pe poke samples showed different domains viz. bacteria (99.08%), viruses (0.65%), eukaryota (0.08%), archaea (0.03%) and unclassified sequences (0.16%). Firmicutes (63.78%) was the most abundant phylum followed by Proteobacteria (29.54%) and Bacteroidetes (5.44%). Bacillus thermoamylovorans was significantly abundant in 3ds and 4ds (p<0.05); Ignatzschineria larvae was significantly abundant in 5ds (p<0.05), whereas, Bacillus subtilis was significantly abundant in Sds (p <0.05). A total of 172 species of Bacillus was detected. In minor abundance, the existence of bacteriophages, archaea, and eukaryotes were also detected. Alpha diversity analysis showed the highest Simpson’s diversity index in Sds comparable to other samples. Similarly, a non-parametric Shannon’s diversity index was also highest in Sds. Good’s coverage of 0.99 was observed in all samples. Beta diversity analysis using PCoA showed no significant clustering. Several species were shared between samples and many species were unique to each sample. In KEGG database, a total number of 33 super-pathways and 173 metabolic sub-pathways were annotated from the metagenomic Open Reading Frames. Predictive functional features of pe poke metagenome revealed the genes for the synthesis and metabolism of wide range of bioactive compounds including various essential amino acids, different vitamins, and enzymes. Spearman’s correlation was inferred between the abundant species and functional features.

This present work is aimed to screen the PGA-producing Bacillus spp. from naturally fermented soybean foods of Arunachal Pradesh in India and to characterize the poly-glutamic acid (PGA) extracted from Bacillus spp. A total of 50 isolates were screened for high stickiness from 165 bacterial isolates isolated from 34 samples viz., grep chhurpi, peha/paeha, peron namsing, and peruñyaan. Based on 16S rRNA gene sequence analysis, 50 isolates were identified as Bacillus spp. Viscosity of 50 species of Bacillus were measured, out of which 7 species of Bacillus showing ≥0.03 Pa.s (30 cP) of viscosity were selected viz., Bacillus velezensis GC1-42, B. siamensis GC4-36, B. subtilis PH3-21, B. subtilis PN1-14, B. subtilis PH6-29, B. tequilensis PN9-22, and B. safensis subsp. safensis PY1-19 for PGA production. Amino acid analysis of PGA extracted from seven species of Bacillus showed high molecular weight (˃600 kDa). B. safensis subsp. safensis PY1-19, isolated from peruñyaan, showed 78.9% of glutamic acid, antagonistic properties against pathogenic bacteria and had the ability to produce phytase with no hemolytic activity. Hence, this strain was selected as a potential starter to prepare peruñyaan at laboratory, and the final product showed high stickiness and viscosity with production of PGA of around 11 g/L.