Yeast powder is not decomposed by yeast, but the nutritional components of yeast extract powder have been decomposed, which makes the speed and efficiency of microbial absorption and utilization higher and the fermentation residue less; At present, yeast extract and yeast extract are basically used in the research of biological fermentation, and yeast powder is mainly used in traditional fermentation industries such as antibiotics.

Wine shell, generally writing wine yeast. After intense cooking, the conidia of Aspergillus were transplanted into white rice, and then kept warm, and hyphae flourished on rice grains, which was called koji. The starch of rice is saccharified under the strong action of amylase of Aspergillus, so it has been used as the raw material of sugar together with malt since ancient times, which is used in wine, sweet wine and soybean paste. Wheat instead of rice is called wheat koji.