Review of the valorization initiatives of brewing and distilling by-products

Beer and spirits are two of the most consumed alcoholic beverages in the world, and their production generates enormous amounts of by-product materials. This ranges from spent grain, spent yeast, spent kieselguhr, trub, carbon dioxide, pot ale, and distilled gin spent botanicals. The present circular economy dynamics and increased awareness on resource use for enhanced sustainable production practices have driven changes and innovations in the management practices and utilization of these by-products. These include food product development, functional food applications, biotechnological applications, and bioactive compounds extraction. As a result, the brewing and distilling sector of the food and drinks industry is beginning to see a shift from conventional uses of by-products such as animal feed to more innovative applications. This review paper therefore explored some of these valorization initiatives and the current state of the art.

Processing and optimisation of complementary food blends from roasted pearl millet (Pennisetum glaucum) and soybean (Glycine max) using response surface modeling

Adequate nutrition is vital during infancy but the high cost of supplemented infant formulae has forced inhabitants of Central and West Africa to depend solely on low-nutrient gruels. Response Surface modelling was used to process a complementary food from roasted pearl millet and Soybean flour. A central composite design was adopted to study the effects of feed composition X1 (5.86-34.14%) and roasting temperature X2 (126-154 °C) on the micronutrients, functional, and sensory profiles of the different blends. The responses were significantly (p < 0.05) affected by the independent factors. For the vitamins in mg/100 g, the thiamin, riboflavin, folate, and β-carotene content ranged from 0.17-0.33, 24-53.50, 1.32-2.29, and 7-22.98, respectively. For the minerals in mg/100 g, the zinc, calcium, potassium, and iron content ranged from 0.35-0.54, 39.5-62.75, 1.2-1.8, and 0.017-0.18, respectively. The viscosity, bulk density, swelling capacity, water absorption capacity, and pH ranged from 1577.5-942.5 cP, 0.74-0.79 g/cm3, 0.10-0.30 ml/g, 1.2-1.4 ml/g, and 4.70-5.70, respectively. The sensory scores were rated highly by the panelists. The optimum processing conditions with a desirability of 0.50 gave 29.28% and 130.39 °C feed composition and roasting temperature, respectively.

The selective breeding and mutagenesis mechanism of high-yielding surfactin Bacillus subtilis strains with atmospheric and room temperature plasma

BACKGROUND

Surfactin, a good biological surfactant, is derived from the metabolites of microorganisms. However, the ability of natural strains to produce surfactin is low, and so the presented study aimed to use a novel mutagenesis technology to increase their yields.

RESULTS

Atmospheric and room temperature plasma (ARTP) was used to conduct mutation breeding of Bacillus subtilis CICC 10721, and a mutant strain M45 with a higher surfactin yield of 34.2% and a stable subculture was screened out. From the fermentation kinetics study, it was found that the maximum cell dry weight, maximum growth rate and surfactin synthesis parameters of the mutant strain M45 were all greater than that of the original strain. Scanning electron microscope and laser scanning confocal microscope observations showed that the spore morphology changed after ARTP treating, and the intracellular Ca²⁺ concentration of the mutant increased. Genome resequencing analysis showed that 66 single nucleotide poymorphism non-synonymous mutation sites occurred in M45, and the identification results of the fermentation broth extract from M45 showed that it is composed of C₁₂ -C₁₆ surfactin.

CONCLUSION

ARTP mutagenesis was found to change the morphology of bacteria, membrane permeability and genes related to the synthesis and secretion of surfactin. The present study provides a basis for industrial production of surfactin and an understanding of the mutagenesis mechanism. © 2021 Society of Chemical Industry.