Biorefinery of Brewery Spent Grain by Solid-State Fermentation and Ionic Liquids

Abstract

Novel environmentally friendly pretreatments have been developed in recent years to improve biomass fractionation. Solid-state fermentation (SSF) and treatment with ionic liquids show low environmental impact and can be used in biorefinery of biomass. In this work, these processes were assessed with brewery spent grain (BSG). First, BSG was used as a substrate to produce cellulases and xylanases by SSF with the fungi Aspergillus brasiliensis CECT 2700 and Trichoderma reesei CECT 2414. Then, BSG was pretreated with the ionic liquid [N1112OH][Gly] and hydrolyzed with the crude enzymatic extracts. Results showed that SSF of BSG with A. brasiliensis achieved the highest enzyme production; meanwhile, the pretreatment with ionic liquids allowed glucan and xylan fractions to increase and reduce the lignin content. In addition, a mixture of the extracts from both fungi in a ratio of 2.5:0.5 Aspergillus/Trichoderma (v/v) efficiently hydrolyzed the BSG previously treated with the ionic liquid [N1112OH][Gly], reaching saccharification percentages of 80.68%, 54.29%, and 19.58% for glucan, xylan, and arabinan, respectively. In conclusion, the results demonstrated that the BSG biorefinery process developed in this work is an effective way to obtain fermentable sugar-containing solutions, which can be used to produce value-added products.

Harnessing Brewery Spent Grain for Polyhydroxyalkanoate Production

“…The achieved biopolymer titers in the study, PHB at 3.53 g/L and PHB−co−MCL at 3.32 g/L, substantiate the potential of BSG as a raw material for PHA production, thereby reducing production costs through the utilization of valued waste resources [10,40]. Thus, much progress has been made to underscore the feasibility and overall sustainability of PHA production from fermented BSG and agricultural wastes, emphasizing the valorization of waste streams and concomitant development of biodegradable products for various applications [1,10,39,40].…”

“…In turn, these induced enzymatic cocktail extracts, which likely comprise a cadre of ligninases and cellulases, are quite effective alongside ionic liquid exposure in releasing fermentable sugars during breakdown of BSG biomass. [39]. The coupling of SSEH and SSF approaches in turn amplifies PHA yields by up to 54% for BSG, in comparison to SSF alone [18].…”

“…The feasibility of a sustainable biorefinery system for PHA production from lignocellulosic−derived wastes, including BSG, was also examined [39]. Enzymatic cocktails for BSG degradation can be induced by fungal microbes, Aspergillus brasiliensis and Trichoderma reesei, during SSF protocols.…”

Processing of Agricultural Residues with a High Concentration of Structural Carbohydrates into Biogas Using Selective Biological Products

“…Some studies aim to enhance biogas production from rice straw and soybean straw using pretreatment by Trichoderma [9], wheat straw pretreatment with anaerobic digestate [26], etc. Hydrolytic enzyme systems excreted by filamentous fungi, mainly those belonging to the Aspergillus and Trichoderma genera, are among the most efficient extracellular cellulase producers, degrading cellulose and hemicellulose to release fermentable sugars [27,28].…”

Production of Sustainable Postbiotics from Sugarcane Straw for Potential Food Applications

“…Lignocellulosic biomass has grown in importance within the context of biorefinery, which aims to effectively use biomass to produce bioproducts with high-added value with sustainability. The most affordable and copious renewable carbon source currently accessible is lignocellulosic biomass [11]. Despite the potential that postbiotics have in the food industry, they may present some issues related to their production costs, hence, they are less competitive than their counterparts made from plants or chemical compounds.…”