Brewer's spent grain: Characterization and standardization procedure for the enzymatic hydrolysis by Bacillus cereus strain

Abstract

An important way to reuse agroindustrial by-products and to produce added-value products consists of the production of protein hydrolysates. In the current study, we used Brewer's spent grain (BSG), mainly because of its availability and cost, as a substrate for the enzymatic hydrolysis by Bacillus cereus. First, the physicochemical and microbiological characterization of BSG batches from three varieties was carried out. Furthermore, the optimal fermentation upstream processes for enzymatic hydrolysis by B. cereus were defined. Finally, the ability of B. cereus to hydrolyze different fractions of BSG was analyzed and possible synergistic effects of this bacterium along with other proteolytic bacteria were also investigated. Results showed that the naturally associated microflora was predominantly thermophilic aerobic bacteria and the drying process was the better alternative for BSG preservation. Water, lipids, and ash content differed significantly among the three varieties; however, no statistically significant differences were found in the protein content among them. After BSG characterization studies, the following protocol was set to obtain the fermentation substrate (FS): drying at 60°C for 24-48 H; sieving, grinding, and polyphenol extraction with an alcohol-water solution; and finally autoclaving. A synergistic effect was observed when B. cereus was inoculated with Pseudomonas strains in FS.

Extraction and characterization of bio-effectors from agro-food processing by-products as plant growth promoters

“…Results of the chemical characterization of BSG was consistent with Khidzir et al [18] for Mg but differed for Ca and P. The obtained content of N and K is similar to the values previously reported by Gupta et al [19]. High nitrogen content in the BSG raw material is related to the richness in protein as reported by Kotlar et al [20].…”

Characterization of a novel protease fromBacillus cereusand evaluation of an eco-friendly hydrolysis of a brewery byproduct

“…Brewer's spent grain (BSG) (~32.5% protein on a dry basis) was purchased from Antares S.A. (Mar del Plata, Argentina). The BSG was pre‐treated according to the procedure described in Kotlar et al in order to standardize the BSG and to prepare the fermentation medium (FM) comprising the following: 0.32 g/L pre‐treated BSG in 0.2 m Tris–HCl buffer, pH 8. Briefly, the following protocol was set in order to obtain the FM: drying at 60 °C for 24–48 h; sieving; grinding; polyphenol extraction with an alcohol–water solution (30:100); and, finally autoclaving (121 °C for 15 min).…”

Improvement of functional and antimicrobial properties of brewery byproduct hydrolysed enzymatically

“…The BSG was pre-treated according to the procedure describing in Kotlar, Belagardi, and Roura (2011) in order to standardize the hydrolysis substrate (HS). Enzymatic hydrolysis was produced in our lab following the procedure described in Section 2.1.…”