Conversion of brewery spent grain into 2,3-butanediol: a sustainable approach using biomass treatments
Abstract
This study explores the potential use of brewer’s spent grain (BSG), an abundant byproduct of the brewing industry, as a carbon source to produce 2,3-butanediol (2,3-BD). BSG was subjected to four pretreatment methods using sulfuric acid (H2SO4), phosphoric acid (H3PO4), sodium hydroxide (NaOH), and ammonium hydroxide (NH4OH). The liquid hydrolysates obtained from these treatments were used as fermentation media for 2,3-BD production by two bacterial strains (Klebsiella pneumoniae BLh-1 and Pantoea agglomerans BL1) under orbital shaking conditions. The H2SO4 hydrolysate resulted in the highest production and productivity of 2,3-BD (21.71 g∙L−1 and 0.90 g∙(L∙h)−1, respectively). In contrast, hydrolysates from H3PO4 resulted in the lowest yields and productivities for both strains, with productivity values of 0.32 g∙(L∙h)−1 for K. pneumoniae BLh-1 and 0.27 g∙(L∙h)−1 for P. agglomerans BL1. Alkaline treatments released only small amounts of glucose; however, they indicated a potential utilization of phenolic compounds, especially ferulic acid, as a carbon source by microorganisms. This study underscores the promise of leveraging an inexpensive and abundant source of lignocellulosic biomass to produce key intermediates for the chemical industry.
