Open AccessBrewers’ spent grain liquor as a feedstock for lactate production with Lactobacillus delbrueckii subsp. lactis
Author(s) -
Akermann Alexander,
Weiermüller Jens,
Christmann Jens,
Guirande Léa,
Glaser Gregor,
Knaus Annette,
Ulber Roland
Publication year - 2020
Publication title -
engineering in life sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.547
H-Index - 57
eISSN - 1618-2863
pISSN - 1618-0240
DOI - 10.1002/elsc.201900143
Subject(s) - brewing , fermentation , food science , raw material , bioprocess , yeast , lactobacillus , corn steep liquor , yeast extract , chemistry , hydrolysis , biochemistry , biology , organic chemistry , paleontology
Brewers’ spent grain (BSG) is a low‐cost by‐product of the brewing process. BSG liquor names the liquid components of BSG, mainly glucose, maltose, and long‐chain α‐1,4‐glycosidic bond glucose oligomers. These substances should be separated in existing BSG biorefineries, as they might lead to an increased formation of microbe‐inhibiting compounds in well‐established hydrothermal/enzymatic saccharification processes. In most cases, this liquid fraction is discarded. The present study presents for the first time an optimized process with BSG liquor for the purpose of producing bulk chemicals (e.g., lactate) in relevant concentrations. The process comprises the application of yeast extract, produced from own brewing processes, as the sole supplemented complex constituent in a simultaneous fermentation and saccharification process. Kinetic parameters for the final optimized process conditions with the organism Lactobacillus delbrueckii subsp. lactis were: maximum specific growth rate µ max = 0.47 h −1 , maximum lactate concentration c Lac, max = 79.06 g L −1 , process yield Y PS = 0.89 g Lac g Sugar −1 , lactate production rate q P = 4.18 g Lac g CDW −1 h −1 , and productivity P 15 h = 4.93 g Lac L −1 h −1 . BSG liquor, linked with yeast extract from Brewers’ yeast, can be a promising substrate for further bioprocess engineering tasks and contribute to a holistic and sustainable usage of Brewers’ spent grain.