Characterization of the Microbial Community in a Caproic Acid-producing Bacterial Consortium (CAPBC) and Optimization of a Fermentative Medium by Taguchi Design.

The caproic acid-producing bacterial consortium (CAPBC) J₃₀, isolated from Chinese Luzhou-flavored liquor distillery's pit mud, produces caproic acid as a metabolite. Constructed a 16S rDNA gene clone library and analyzed amplified ribosomal DNA restriction analysis, Clostridium genus was found predominating in CAPBC J₃₀ and C. kluyveri was the chief contributor to its caproic acid-producing ability Then based on the Daqu extraction medium, effects of different carbon sources, nitrogen sources and growth factors on the caproic acid-producing ability were investigated, among which six key factors were chosen and optimized by Taguchi design. The estimated optimal medium was the Daqu extraction medium added 10 g⋅^-1 sodium acetate, ethanol 15 ml⋅^-1, liquor tailing 15 ml⋅^-1, urea 3g⋅1^-1, yellow mud extraction 1 ml⋅^-1, and (NH₄)₂S0₄ 0.5 g⋅1^-1. After cultivated in this optimized medium for 15 days at 37°C, the caproic acid yield was up to 5024.11 mg⋅^-1. This optimal medium will help to produce high caproic acid of CAPBC J₃₀ to circumvent bottlenecks encountered in the high effective and adaptable ingredients in the field of Chinses Luzhou-dwortd liquor manufacture. [ABSTRACT FROM AUTHOR]