Safe yeast in nature

Kluyveromyces marxianus is an unconventional yeast. It is a strain with great development potential after Saccharomyces cerevisiae. It was isolated and obtained more than a century ago. It is widely found in yoghurt, fruit, kefir, etc. It is a safe yeast in nature.

　　The study pointed out that Kluyveromyces marxianus can secrete more than 10 kinds of enzymes such as inulinase, β-galactosidase, carboxypeptidase, aminopeptidase and lipase, and is a natural enzyme factory. Different strains of Kluyveromyces marxianus also have differences in their ability to produce enzymes, and the ideal enzyme production interval can be obtained by strain screening. Kluyveromyces marxianus is easy to realize genetic engineering transformation, can produce various enzymes in a targeted manner, and plays an important role in enzyme-related industries.

　　Yogurt is the most common fermented dairy product, which is usually fermented by lactic acid bacteria. The reason why yogurt is sour is because lactic acid bacteria convert the carbon source of sugar into lactic acid. Lactose is the most important sugar in cow's milk and almost the only carbon source for pure milk fermentation. However, the use of lactose by lactic acid bacteria is not easy. It directly leads to a slow fermentation process, so a certain amount of sucrose and fructose syrup are usually added to yogurt as a carbon source and flavoring agent for fermentation.

Kluyveromyces marxianus is rich in β-galactosidase, which can quickly convert lactose in cow's milk. Under the condition of synergy with lactic acid bacteria, it can increase the amount of lactose decomposition, reduce the time required for fermentation and other sugars. Add to. At the same time, Kluyveromyces marxianus can produce functional galactooligosaccharides, thereby increasing the functionality of fermented milk.

　　Dietary fiber is an important functional ingredient. In plants, dietary fiber is mainly insoluble dietary fiber. From the perspective of functional integrity, insoluble dietary fiber is far inferior to soluble dietary fiber. Therefore, increasing the content of soluble dietary fiber in plant-based raw materials is an important direction for raw material modification.

Kluyveromyces marxianus can produce a variety of cellulases such as β-glucosidase, exoglucanase, and can degrade cellulose to produce soluble dietary fiber, and the degradation of cellulose is also beneficial to be wrapped in it The release of the active substance increases the functionality of the product.

　　Kluyveromyces marxianus has many advantages in application. The most researched is the use of ethanol fermentation of processing waste. For example, ethanol is fermented in a molasses environment with a high sugar concentration, and cellulose degradation products that cannot be fermented by other Saccharomyces cerevisiae continue to ferment. Although my country has approved Kluyveromyces marxianus as a new food raw material in 2013, its related products are rare, the market does not pay enough attention, and the value is not well reflected. Research on its application level needs to be deepened.