Brewers' spent grain and thin stillage as raw materials inl-(+)-lactic acid fermentation

Abstract

Brewer's spent grain (BSG) hydrolysates were used for l‐(+)‐lactic acid (LA) fermentation by Lactobacillus rhamnosus ATCC 7469. In this study the effect of the addition of various amounts of thin stillage (TS) in BSG hydrolysate on LA fermentation parameters were evaluated. TS addition significantly increased utilization of glucose by up to 43.0%. In batch fermentation the highest LA concentration and volumetric productivity of 31.0 g/L, and 0.93 g/L/h, respectively, were obtained with the addition of 50% TS. L. rhamnosus cell viability also increased with the addition of 50% TS (by 2.4%). TS addition significantly increased free amino nitrogen concentration (by up to 209%) which is important for bacterial growth. A strong positive correlation between free amino nitrogen and LA concentration was noted. Compared with the results obtained in the batch fermentation (50% TS), significantly higher LA concentration, yield and volumetric productivity (54.8, 1.9 and 4.0%, respectively) were achieved in fed‐batch fermentation with glucose and TS addition. The results suggest that the combination of the by‐products of brewing and bioethanol industries could be suitable for LA production. Copyright © 2017 The Institute of Brewing & Distilling

Conversion of brewers’ spent grain into proteinaceous animal feed using solid state fermentation

“…BSG is derived from malted grain, the main raw material of brewing industry (Khidzir et al 2010). It must be noted that the annual production of BSG exceeds the 30 Mtons, since every hectoliter of beer results in the production of 15-20 kg of BSG (Radosavljevic et al 2017). The annual European production of BSG is estimated to 3.4…”