Cell wall polysaccharides: before and after autolysis of brewer’s yeast

Abstract

Brewer's yeast is used in production of beer since millennia, and it is receiving increased attention because of its distinct fermentation ability and other biological properties. During fermentation, autolysis occurs naturally at the end of growth cycle of yeast. Yeast cell wall provides yeast with osmotic integrity and holds the cell shape upon the cell wall stresses. The cell wall of yeast consists of β-glucans, chitin, mannoproteins, and proteins that cross linked with glycans and a glycolipid anchor. The variation in composition and amount of cell wall polysaccharides during autolysis in response to cell wall stress, laying significant impacts on the autolysis ability of yeast, either benefiting or destroying the flavor of final products. On the other hand, polysaccharides from yeast cell wall show outstanding health effects and are recommended to be used in functional foods. This article reviews the influence of cell wall polysaccharides on yeast autolysis, covering cell wall structure changings during autolysis, and functions and possible applications of cell wall components derived from yeast autolysis.

Cell wall and cell membrane defects contribute to reduced cell growth at 28 °C in Phaffia rhodozyma mutant strain MK19

“…In contrast, 28 °C treatment resulted in increased expression of genes associated with mannan component biogenesis; i.e., the genes encoding α-1,3mannosyltransferase (comp11864_c1), α-1,2-mannosyltransferase (comp12286_c0), and α-1,6mannosyltransferase (comp11585_c0). MK19 glucan levels were higher at 28 °C, consistent with previous ndings that higher β-glucan levels are associated with greater stress resistance in yeast strains [32]. In our study, higher glucan level promoted MK19 survival at 28 °C.…”

“…In MK19 at 28 °C, mRNAs of most glucan biosynthesis-related genes were downregulated; these included β-1,3-glucanosyltransferase (comp13450_c0), β-1,3-glucanase (comp11848-co, comp11848-c1), and endo-1,3-α-glucanase agn1 (comp12961_c0, comp10598_c0). Yeast cells sometimes deposit more chitin in lateral walls to compensate for compromised cell integrity [32]. In our study, genes that encode enzymes involved in chitin synthesis were upregulated; these include chitin deacetylase (comp13745), chitin synthase CHS1 (comp12056, comp13627), chitin synthase CHS2 (comp12623, comp13980), and chitin synthase CHS2,1,8 (comp14086).…”

Solid-state fermentation of palm kernels by Yarrowia lipolytica modulates the aroma of palm kernel oil

“…It should be noted that, autolysis of yeast during fermentation might have released some aroma precursors such as amino acids, peptides, lipids, polysaccharides, nucleotides and nucleosides, which would in turn impact the aroma composition in obtained PKO after roasting, however, in our view, to a low extent 47–49 . It is known that autolysis usually occurs at the end of stationary growth phase when the fermentable carbon sources are almost depleted and is normally associated with cell death 47,50 . In the current experiment, both amino acids and simple sugars were left with relatively high amount when fermentation was stopped, indicating that nutrients for yeast survive were available.…”

The Effect of Apple Juice Concentration on Cider Fermentation and Properties of the Final Product

“…It should be noted that long-chain fatty acids esters have been previously tied to the onset of cell death [ 39 , 40 , 41 ]. Due to their low permeability through the cell membrane, the long-chain fatty acid esters are released along with other compounds (e.g., amino acids, fatty acids, lipids, glycoproteins, mannoproteins) into the environment during cell autolysis [ 39 ].…”