title: Enhanced viability of Lactobacillus reuteri for probiotics production in mixed solid-state fermentation in the presence of Bacillus subtilis.
abstract: In order to develop a multi-microbe probiotic preparation of Lactobacillus reuteri G8-5 and Bacillus subtilis MA139 in solid-state fermentation, a series of parameters were optimized sequentially in shake flask culture. The effect of supplementation of B. subtilis MA139 as starters on the viability of L. reuteri G8-5 was also explored. The results showed that the optimized process was as follows: water content, 50 %; initial pH of diluted molasses, 6.5; inocula volume, 2 %; flask dry contents, 30∼35 g/250 g without sterilization; and fermentation time, 2 days. The multi-microbial preparations finally provided the maximum concentration of Lactobacillus of about 9.01 ± 0.15 log CFU/g and spores of Bacillus of about 10.30 ± 0.08 log CFU/g. Compared with pure fermentation of L. reuteri G8-5, significantly high viable cells, low value of pH, and reducing sugar in solid substrates were achieved in mixed fermentation in the presence of B. subtilis MA139 (P < 0.05). Meanwhile, the mixed fermentation showed the significantly higher antimicrobial activity against E. coli K88 (P < 0.05). Based on the overall results, the optimized process enhanced the production of multi-microbe probiotics in solid-state fermentation with low cost. Moreover, the viability of L. reuteri G8-5 could be significantly enhanced in the presence of B. subtilis MA139 in solid-state fermentation, which favored the production of probiotics for animal use.
authors.affiliation: Key Lab for Microorganisms and Biotransformation, South-Central University for Nationalities, No. 708, Minyuan Road, Hongshan District, Wuhan City, Hubei Province, 430074, China.
authors.forename: Yi-Ran
authors.initials: YR
authors.lastname: Zhang
authors.forename: Hai-Rong
authors.initials: HR
authors.lastname: Xiong
authors.forename: Xiao-Hua
authors.initials: XH
authors.lastname: Guo
mesh_terms: D001412:Bacillus subtilis / Q000254:growth & development*; D058491:Bacterial Load; D002241:Carbohydrates; D003470:Culture Media / Q000737:chemistry; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D052200:Limosilactobacillus reuteri / Q000254:growth & development / Q000302:isolation & purification / Q000502:physiology*; D056265:Microbial Interactions; D050296:Microbial Viability; D019936:Probiotics / Q000302:isolation & purification*
chemical_list: D002241:Carbohydrates; D003470:Culture Media