Filtration technology for beer and beer yeast treatment

Solid-liquid filtration processes are crucial for the production of beer. Clarification of the green beer generates a clear and bright product with extended colloidal and microbiological shelf live. Conventionally, clear filtration is based on pre-coat filtration using filter aids, such as diatomaceous earth (Kieselguhr). However, the application of Kieselguhr requires strict adherence to occupational safety and health protection, as it is classified as a hazardous substance by the World Health Organisation and can lead to lung diseases. Furthermore, significant amounts of waste filter aids are generated. An alternative to pre-coat filtration is microfiltration that avoids the generation of hazardous wastes. Microfiltration can also be applied in beer yeast treatment. This article highlights major concepts and restriction of the filtration processes.

Selection of Bacillus subtilis strains capable of producing β-glucanase supporting the hydrolysis of yeast cell walls

The selection of B. subtilis strains was carried out with 15 strains from the collections of the Vietnam National University of Agriculture and the University of Economic and Technical Industries, Hanoi, Vietnam. To investigate the specific ability of β-glucanase in supporting the hydrolysis of beer yeast cells, CMC substrates in enzyme-activated test media of traditional methods was replaced by yeast cell walls in this study. The B. subtilis strains were activated on Nutrient Broth culture and then transplanted into MT3 culture for producing β-glucanase. Optical density (OD600nm) measurement was used to estimate the bacterial density. The β-glucanase activity formed by bacteria cells free supernatant was quantified by agar diffusion method on the enzyme-activated test media MT4. Two B. Subtilis strains , BG21 and BG15, were selected based on their largest clear-zones on agar plates. By modifying the values of the affecting factors and keeping the remaining influencing factors unchanged, it was determined that the B. subtilis BG21 and BG15 strains produced the highest biomass at the conditions of the culture time of 24 and 28 h, at pH 7.0, and at 37oC, respectively; furthermore, the highest activity of β-glucanase of the two strains BG21 and BG15 was exhibited at the culture time of 52 and 56 h, at pH 7.0, and at 37oC, respectively.Practical applicationsBacillus subtilis strains with the highest β-glucanase producing ability will be used for the production of biological products containing B. subtilis and β-glucanase which supports the hydrolysis of the beer yeast cells in the production of pig feed.

RESEARCH OF THE INFLUENCE OF THE PROCESS OF REMOVE THE BITTERNESS OF RESIDUAL BEER YEAST ON THE AMINO ACID COMPOSITION

The article identifies factors that impede the widespread use of residual brewer's yeast in the feed industry. The methodology and stages of processing residual brewer's yeast with alkali and their drying are described. Experimental studies were carried out to determine the rational technological regimes for processing brewer's yeast. Presents data on the amino acid content in processed and untreated residual brewer's yeast

Biological parameters of adult of Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae) fed on Asteraceae pollen under laboratory conditions

The objective of this study was to evaluate the biological parameters and the preference of Artemisia tridentata Nutt (Asteraceae) industrial pollen grains and beer yeast by Ch. externa adults for a more suitable diet for laboratory rearing. To conduct the experiment, 105 adults of newly emerged Ch. externa were used. They were placed in PVC cages (10.0 cm high x 10.0 cm in diameter), closed with PVC plastic film, each cage contained two females and one male (2: 1), and each cage was placed on a diet, being they are: Artemisia pollen (A. tridentata), artemisia + honey pollen (mixed), beer yeast, beer yeast + honey (mixed), water, honey, artemisia pollen + honey (separated). The diets 2 (artemisia pollen + mixed honey), 3 (brewer's yeast) and 4 (brewer's yeast + mixed honey) were shown to be statistically good diets at 5% confidence, according to the results analyzed for the parameters fecundity, oviposition, oviposition, mean number of eggs/day and viability of eggs. As the other diets 1 (artemisia pollen), 5 (water), 6 (honey) and 7 (artemisia pollen + separated honey) did not obtain statistically results, because they had means zero or close to zero, so these treatments are not feasible for a rearing of Ch. externa in the laboratory.