Beer production includes the formation of different by-products such as wastewater, spent grains, spent hops, and yeast. In addition to these well-known by-products, it is necessary to mention germ/rootlets, which also remain after the malting process. Given that a huge amount of beer is produced annually worldwide, by-products are available in large quantities throughout the year. Spent grains, spent hops, and spent yeasts are high-energy raw materials that possess a great potential for application in the branch of biotechnology, and the food industry, but these by-products are commonly used as livestock feed, disposed of in the fields, or incinerated. Breweries by-products can be utilized for microalgae production, biofuel production, extraction of proteins, polyphenolic, antioxidative substances, etc. This paper aims to address each of these by-products with an emphasis on their possible application in biotechnology and other industries.

Brewers’ spent grain (BSG) is the main solid by-product of the brewing process and is typically disposed of as cattle feed. In this study, BSG was evaluated as a substrate for the production of polyphenols and the lignin-degrading enzyme laccase using fungal solid-state fermentation by Trametes versicolor. Laccases are finding increasing applications in the food industry and polyphenols have benefits for human health. After 14 days of fermentation with T. versicolor, there was a 3.4-fold increase in the extraction of total polyphenols compared with untreated BSG. Using BSG as the sole source of carbon and nitrogen, maximum laccase activity was achieved after seven days of treatment with an activity of 560 U/L. Based on these results, BSG is suggested to be a good lignocellulose waste material to produce value-added products such as the enzyme laccase and polyphenols. Copyright © 2018 The Institute of Brewing & Distilling

Malting and brewing processes should be performed under process conditions in a way that minimizes beer bitterness, maximizes polyphenol content and reduces the amount of raw materials ending up in solution in the form of hazes, particles and precipitates. This work examined the influence of different mashing temperature conditions and boiling procedures on the total polyphenol content, bitterness and haze of pale and dark lager beers produced on an industrial scale. Two hop types (hop pellets and/or hop extract) and different hop varieties (Hallertau Magnum, Styrian Goldings, Saaz, Aurora and Sladek) were utilized with varying times of hop addition into the wort. Measurements of total polyphenols, colour, bitterness, alcohol content, CO₂ and pH were carried out on the beer samples. Results showed that pale lager beers had a lower total polyphenol concentration (110–179 mg/L) than dark beers (230–260 mg/L). Using hop extracts instead of hop pellets led to a lower total polyphenol concentration and to less beer foam creation. The change in the proteolytic temperature during mashing only had an influence on the total polyphenol content in the pale lager beer hopped with the pellets. Conducting proteolysis over a 20 min period led to a haze increase in all of the beers produced. In the dark beer, the haze was substantial after just 10 min at 52°C. Copyright © 2015 The Institute of Brewing & Distilling

Ćupter is Herzegovinian candy made of must and flour/semolina. Much research about the incorporation of brewers’ spent grains into the human diet has been published. The purpose of this study was to partially replace semolina (Samples 1 and 2) and flour (Samples 3 and 4) with brewers’ spent grains originating from industrial (Samples 1 and 4) and craft breweries (Samples 2 and 3) and study nutritive, chemical, and preference properties of the product. In this research, the authors aimed to find application of this already proven functional ingredient in ćupter production. Values for pH were higher for all samples compared to the traditional recipe. Samples produced with flour had higher values of water activity (0.86 ± 0.01) and moisture (41.82 ± 1.68 and 41.11 ± 1.41). Ash content increased with BSG addition, but between samples, there were no significant differences. Collected data showed significant differences in fat levels. Higher protein content was measured for Samples 4 (6.60 ± 0.17) and 1 (6.13 ± 0.07). The highest total sugar content was measured for Sample 1. The general appearance for all samples was “moderately like”. Nutritive value was improved with the addition of BSG, but recipes and drying should be modified to improve consumer acceptance.

The use of bakery leftovers as a substitute for malt in brewing represents a sustainable approach that reduces costs and waste. In this paper, the fermentation of brewer’s spent grain, a byproduct of beer production, is integrated with the use of non-conventional yeasts to unlock the potential of yeasts beyond the common Saccharomyces species. This creates a circular system where byproducts are efficiently utilized, fostering sustainability and innovation in food production. This study assesses the fermentative capabilities of the non-conventional yeast Yarrowia lipolytica and the lactic acid bacterium Lactobacillus acidophilus DSM 20079 on brewer’s spent grain, a byproduct from brewing beer with old wheat bread and barley malt. Both hydrolyzed with a cell-wall-degrading enzyme complex and non-hydrolyzed brewer’s spent grain were evaluated for key fermentation indicators such as the number of microbial cells, total titratable acidity, pH, reduced sugar content, and fatty acid composition. The findings reveal that Yarrowia lipolytica effectively fermented brewer’s spent grain without prior hydrolysis, maintaining a balanced fatty acid profile. The combined action of both microorganisms provided optimal fermentation outcomes, offering a promising approach for valorizing brewer’s spent grain, reducing waste, and promoting a circular economy in the brewing and food industries.