Advances in yeast autolysis technology - a faster and safer new bioprocess

Abstract

The yeast autolysis process - an endogenous and irreversible lytic event, which occurs in cells caused by the action of intracellular enzymes, proteases and carbohydrases - is a well-known and an economic process, however, there is a constant risk of serious microbial contamination since there are many nutrients in the broth and this process is slow, favoring the growing of pathogens. The present work comes up with an attempt to accelerate the autolysis of Saccharomyces cerevisiae with focus on the high yield of yeast extract production through a fast, economic and simple technology. The proposed strategy is based on decreasing the pH of the yeast suspension at the beginning of autolysis through an acid shock to activate the cell autolytic system under stressful conditions of temperature and pH. The influence of cell concentration, temperature, time and acid shock at the beginning of the autolysis on yeast extract yields were studied. The best yields of proteins and total solids were observed for autolysis treated with acid shock (H2SO4 10 µL/g of dried yeast and final pH 4.4) at 60 °C (36, 84% of protein and 48, 47% of total solids extracted) and gradual increase of temperature 45 to 60 °C (41.20% of protein and 58.48% of total solids extracted). The shock could increase the speed of the process since the control reached about 30% of extract at 60 °C and the same experiment, however, with acid shock reached more than 43% in 12 h. When considering time in an industrial scale, it could be noted that the time was very important for the productivity as well as avoiding risk of pathogen contamination in autolysis. These results were very relevant for industrial purposes in the production of yeast extract, autolyzed yeast and glucan and mannan.

Antioxidant Activity of Special Functional Beers

“…1/D) on the twentieth day of fermentation, when the concentration of polyphenols corresponding to 3.100 g/L GAE was determined. However, it is likely that this effect is also a consequence of yeast autolysis, in which dying cells release their contents into the surrounding beer [36]. In typical brewing processes, yeast autolysis is not a significant problem.…”

Đánh giá và ứng dụng dịch thủy phân bã men bia trong sản xuất acid lactic sử dụng Lactobacillus casei

“…Huyền phù được khuấy trong 10 phút và sau đó rửa hai đến ba lần bằng nước cất đã khử trùng. Sau đó, huyền phù được ly tâm ở 5.000 vòng/phút trong 15 phút ở 4°C để thu được các tế bào men bia và trữ lạnh cho đến khi sử dụng (Alves et al, 2021). Thu nhận dịch thủy phân bằng phương pháp cơ học được thực hiện như sau: Sinh khối nấm men được phối trộn với nước cất theo tỉ lệ 1:3 và hấp ở nhiệt độ 121°C trong 20 phút bằng nồi hấp khử trùng.…”

A Review: Using Yeast Extract as Feed Additive in Pig Diets

“…After fermentation process, the yeast cells were washed, centrifuged, heated, and dried (Håkenåsen, 2017). There are two yeast extraction production processes: autolysis, using the yeast's own enzymes or hydrolysis, using added exogenous enzymes (Anwar et al, 2017;Alves et al, 2021). Once the lysis process is complete, the yeast extract (the intracellular soluble fraction) and the cell walls are separated using centrifugation before being dried (Bzducha-Wróbel et al, 2014).…”