Through genetic modification of glucanase and pectinase of dry wine yeast, the metabolic activity of the strain was improved and the sensory inspection of wine was better. Adding exogenous enzymes to improve the aroma of wine is a consistent practice in wineries, although some unknown enzyme mixtures have been added. Therefore, the expression of the coding gene of Saccharomyces cerevisiae-pectinase from trichoderma longibrachiatum in wine yeast is directly related to the aroma of wine. Other glucanases and glycosides can hydrolyze terpenoids with glycoside chains, and release terpenoids can increase the flavor of wine (Querol et al., 1996). In addition, exo -β- 1, 3-glucanase (Dubordieu et al., 1985) isolated from Trichoderma harzianum can hydrolyze β- 1, 3-glucan and β- 1, 6-glucan produced by botrytis cinerea, which can be used to hydrolyze polymers in brewing industry.
10. 10.3.2 beer
The β -glucan enzyme preparation used in beer can degrade β -glucan produced by malt and solve the turbidity caused by precipitation in beer. It is feasible to add commercial β -glucan enzyme preparation for external use, but commercial preparations usually contain other adverse activities. In order to solve this problem, the exo-β- 1 4 glucanase coding gene of Trichoderma reesei was expressed in Saccharomyces cerevisiae. The recombinant yeast strain can be stably expressed under non-selective conditions, and the exoglucanase can be detected on extracellular medium. This recombinant yeast improves the filtration ability of wort and the beer quality is very good (Xie et al., 1995).
10. 10.3.3 bread
Wheat flour contains a lot of amylase but lacks α-amylase, which is the best enzyme to degrade bread dough. The α -amylase used in bread industry comes from the enzyme preparations of malt, bacteria and fungi. The latter can mostly improve the rheology of bread dough. Under the control of promoter ACT 1, the α -amylase expressed by transgenic baking yeast can reflect the optimal expression level of the enzyme. Compared with the control group, the bread fermented dough with α -amylase is softer, which prevents the bread from hardening and prolongs the shelf life (Randez-Gil et al., 1995).
10. 10.3.4 Other uses
The purified lyase can be used to explain the structure of fungal glucan and fungal cell wall (Pitson et al., 1993). The 47kDa Lvmu endonuclease -A- 1, 3- glucanase (Hasegawa et al., 1969) was used to determine the structure of polysaccharide and isolate the whole sugar chain fragment from the cell wall of Aspergillus flavus. β- 1 6 glucanase Ⅱ of Trichoderma harzianum CECT24 13 can recognize protein of Saccharomyces cerevisiae and β- 1, 3-/β- 1, 6 phosphodiester bond bound to protein cell wall (Kapteyn et al., 1996). In addition, these enzymes are also used to identify β -glucan in cereals, which is an important nutritional parameter (brenes et al., 1993). Wheat seedling essence is a β -glucan enzyme preparation from Trichoderma reesei, which is used as a food additive. Eating food with malt extract has no toxic effect on mice and chickens (Coenen, 1995). Experiments were carried out on barley with endoglucanase mixtures from Lvmu mold (Vranjes et al., 1, 3 and β- 1, 4). The results show that endoglucanase can really affect the utilization of organic matter and the degradation of fiber.
Possible applications of purified fungal enzymes in other fields include the transformation of seaweed biomass and fermentable sugar, the clinical application of polysaccharide hydrolysis and polysaccharide synthesis (Pitson et al., 1993).