Optimizing the detoxification conditions of distiller's grains hydrolysate for tetramethylpyrazine fermentation by Bacillus sp. TTMP20

Distiller's grains (DGS) are the main byproduct of the brewing industry and a type of lignocellulosic biomass. In this study DGS were pretreated with water, dilute sulfuric acid, and sodium hydroxide to obtain hydrolysates for the fermentation of tetramethylpyrazine (TTMP). Acid-treated hydrolysate produced the highest TTMP yield. Then detoxification conditions of acid-treated hydrolysate including activated carbon dosage, pH, temperature, and time were optimized for the removal of some inhibitors such as acids, phenols, furfural and 5-hydroxymethyl-2-furaldehyde (HMF), and TTMP production. Under optimal detoxification conditions (activated carbon dosage of 3.0%, pH of 4.0, temperature of 60 celcius, and time of 60 min), almost all inhibitors were removed (83.82% acids, 96.47% phenols, 94.61% furfural and 91.87% HMF). In comparison to the control, this improved detoxification boosted the TTMP yield of Bacillus sp. TTMP20 by 1.27 times. Our strategy provided a suitable way for TTMP production from DGS, which achieved efficient resource utilization of industrial waste DGS.

Automated summary

In this study, distiller's grains were pretreated and detoxified to improve the production of tetramethylpyrazine. The optimal conditions for detoxification resulted in a significant increase in tetramethylpyrazine yield. This research provides a viable method for tetramethylpyrazine production from distiller's grains.