Biorefinery of brewery spent grain by solid-state fermentation and ionic liquids

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.São Paulo Research Foundation | Ref. 2018/25511-1São Paulo Research Foundation | Ref. 2021/15138-4National Council for Scientific and Technological Development | Ref. 408783/2021-4National Council for Scientific and Technological Development | Ref. 312923/2020-1Xunta de Galicia | Ref. GPC-ED431B 2021/23Ministerio de Ciencia e Innovación | Ref. PID2020-115879RB-I0

Biorefinería de residuos cervexeiros para producir moléculas bioactivas de interese alimentario ( bacteriocinas e biosurfactantes)

Proponse empregar dous residuos, bagazo procedente de empresas vitivinícolas e cervexeiras, para a produción de moléculas bioactivas con aplicación no sector alimentario (bacteriocinas e biosurfactantes). Estudarase a hidrólise encimática como método de fraccionamento a fin de transformar a fibra vexetal en azucres fermentables. Para isto proponse a liberación ad hoc de encimas hidrolíticas empregando procesos de fermentación en estado sólido, estudar o pretratamento da biomasa con líquidos iónicos para retirar a lignina e realizar a hidrólise encimática incluíndo o estudo de novos biorreactores. Finalmente ensaiaranse cepas comerciais e patagónicas para producir moléculas bioactivas, concluíndo cun escalado do proceso.Se plantea utilizar dos residuos, bagazo procedente de empresas vitivinícolas y cerveceras, para la producción de moléculas bioactivas con aplicación en el sector alimentario (bacteriocinas y biosurfactantes). Se estudiará la hidrólisis enzimática como método de fraccionamiento a fin de transformar la fibra vegetal en azúcares fermentables. Para ello se plantea la liberación ad hoc de enzimas hidrolíticas empleando procesos de fermentación en estado sólido, estudiar el pretratamiento de la biomasa con líquidos iónicos para retirar la lignina y realizar la hidrólisis enzimática incluyendo el estudio de novedosos biorreactores. Finalmente se ensayarán cepas comerciales y patagónicas para producir moléculas bioactivas, concluyendo con un escalado del proceso.It is proposed the use of two residues, bagasse from wine and beer companies, for the production of bioactive molecules with applications in the food sector (bacteriocins and biosurfactants). The enzymatic hydrolysis as fractionation method to transform vegetable fibers into fermentable sugars will be studied. Therefore, it will be assayed the ad hoc release of hydrolytic enzymes by solid-state fermentation, the pretreatment of biomass with ionic liquids to remove lignin and the final enzymatic hydrolysis including the study of novel bioreactors. Finally, commercial and Patagonian strains will be tested to produce bioactive molecules, concluding with a scale-up process.Xunta de Galicia | Ref. ED481A-2017/32

Enhancing the saccharification of pretreated chestnut burrs to produce bacteriocins

The present study aims to valorize chestnut burrs, an important lignocellulosic waste, through a biorefinery concept. A solid residue rich in glucan (41.36 ± 0.59 %) and lignin (39.06 ± 0.01 %) obtained from a previous process of pre-hydrolysis was subjected to four treatments with water or NaOH to enhance enzymatic hydrolysis. Saccharification was performed using different ratios of commercial cellulases and β-glucosidases and at controlled pH 4.8 or 6.0 (with citrate buffer) or uncontrolled pH. Carbohydrate-rich solutions with or without nutrients were used to produce bacteriocins by Lactobacillus plantarum CECT 211. The use of NaOH at high temperatures (120 and 130 °C) was the most suitable treatment to improve saccharification. Regarding the production of bacteriocins, the best result was obtained using the enzymatic solution obtained at controlled pH 6.0, supplemented with MRS broth nutrients (except glucose). Thus, the concentrations of bacteriocins obtained in this culture medium (9.21 BU/mL) was 1.22 and 1.98 times higher than those obtained in the nutrient supplemented medium buffered at pH 4.8 (7.56 BU/mL) and in the commercial MRS broth (4.65 BU/mL), respectively. These results highlight the feasibility of the technology developed in this work.Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGXunta de Galicia | Ref. ED481B 2018/073Xunta de Galicia | Ref. ED431B 2018/5