AUTHOR=Qin Huibin , Sun Qinghui , Pan Xuewei , Qiao Zhijun , Yang Hongjiang 

TITLE=Microbial Diversity and Biochemical Analysis of Suanzhou: A Traditional Chinese Fermented Cereal Gruel

JOURNAL=Frontiers in Microbiology

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2016.01311

DOI=10.3389/fmicb.2016.01311

ISSN=1664-302X

ABSTRACT=<p>Suanzhou as a traditional Chinese gruel is fermented from proso millet and millet. The biochemical analysis showed Suanzhou had relatively high concentrations of lactic acid, acetic acid, and free amino acids. The metagenomics of Suanzhou were studied, with the analysis of the V4 region of 16S rRNA gene, the genera <italic>Lactobacillus</italic> and <italic>Acetobacter</italic> were found dominant with the average abundance of 58.2 and 24.4%, respectively; and with the analysis of the ITS1 region between 18S and 5.8S rRNA genes, 97.3% of the fungal community was found belonging to the genus <italic>Pichia</italic> and 2.7% belonging to five other genera. Moreover, the isolates recovered from 59 Suanzhou samples with various media were identified with the 16S rRNA or 18S rRNA gene analyses. <italic>Lactobacillus fermentum</italic> (26.9%), <italic>L. pentosus</italic> (19.4%), <italic>L. casei</italic> (17.9%), and <italic>L. brevis</italic> (16.4%) were the four dominant <italic>Lactobacillus</italic> species; <italic>Acetobacter lovaniensis</italic> (38.1%), <italic>A. syzygii</italic> (16.7%), <italic>A. okinawensis</italic> (16.7%), and <italic>A. indonesiensis</italic> (11.9%) were the four dominant <italic>Acetobacter</italic> species; and <italic>Pichia kudriavzevii</italic> (55.8%) and <italic>Galactomyces geotrichum</italic> (23.1%) were the two dominant fungal species. Additionally, <italic>L. pentosus</italic> p28-c and <italic>L. casei</italic> h28-c1 were selected for the fermentations mimicking the natural process. Collectively, our data demonstrate that Suanzhou is a nutritional food high in free amino acids and organic acids. Diverse <italic>Lactobacillus, Acetobacter</italic>, and yeast species are identified as the dominant microorganisms in Suanzhou. The isolated strains can be further characterized and used as starters for the industrial production of Suanzhou safely.</p>