Microbial community structure of pit mud in a Chinese strong aromatic liquor fermentation pit

Abstract

Pits are necessary solid bioreactors for the production of Chinese strong aromatic liquor, and the microbial community in these pits significantly affects the quality and yield of the liquor. In this study, the microbial community structures of different aged pit muds were evaluated by phospholipid fatty acid analysis. The results indicated that the microbial community was composed of bacteria, actinomycetes and fungi, with Gram-positive (G+) bacteria and anaerobic bacteria being dominant. The biomass of the pit mud increased and the microbial community shifted to G+ bacteria as the pit age increased. Principal component analysis showed that PC1 consisted mainly of fatty acids of saturated (15:0, 16:0 and 18:0), methyl-branched (a15:0, i16:0, a16:0, i17:0 and 8Me18:0), polyunsaturated (16:1ω7c, 16:1ω9) and cyclopropane (cy17:0 and cy19:0), and PC2 mainly of 18:1ω9, 18:1ω10 and a14:0, The characteristics of the microbial community structure in the pit mud resulted from the stress effects of low oxygen concentration, low pH and a high alcohol concentration. Copyright © 2013 The Institute of Brewing & Distilling