Resumen

BERNAL-RUIZ, Marcela et al. Brewer's spent grain as substrate for enzyme and reducing sugar production using Pénicillium sp. HC1. Rev. acad. colomb. cienc. exact. fis. nat. [online]. 2021, vol.45, n.176, pp.850-863.  Epub 04-Feb-2022. ISSN 0370-3908.  https://doi.org/10.18257/raccefyn.1379.

Brewer's spent grain (BSG) is the main solid waste from the brewing process. It is recognized as a valuable resource for biobased industries because of its composition, high availability, and low cost. The objective of this study was to employ BSG as a substrate to produce the enzymes endoglucanase, cellobiohydrolase, β-glucosidase, and xylanase, as well as reducing sugars using Pénicillium sp. HC1. For enzyme production, we evaluated BSG submerged fermentation at different concentrations (1%, 3%, and 5%, w/v) and two sources of nitrogen (yeast extract and ammonium sulfate) on different days (6, 10, and 12) in a 100 mL Erlenmeyer flask. The highest enzyme activity was obtained after 10 days. The enzyme extract obtained using 3% BSG (w/v) and 5 g L-1 of ammonium sulfate showed the highest xylanase activity (25013 ± 1075 U L-1). Using BSG 5% (w/v) without nitrogen supplementation, the endoglucanase activity was 909.7±14.2 U L-1 while under the same conditions but using BSG 3% (w/v), the β-glucosidase and cellobiohydrolase activity was 3268.6 ±229.9 U L-1 and 103.15±8.1 U L-1, respectively. Maximum reducing sugar concentrations using an enzyme dosage of 1000 U g-1 of xylanase were: 2.7 g L-1 xylose, 1.7 g L-1 arabinose, and 3.3 g L-1 glucose after 6 h of hydrolysis. Results demonstrated it is possible to produce enzymes and reducing sugars using Pénicillium sp. HC1 and BSG as substrate and BSG grinding only as pretreatment.

Palabras clave : Brewer's spent grain; Pénicillium sp; Xylanase; Reducing sugars; Hydrolysate, cellulase production.

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