Beniwal Arun, Saini Priyanka, Kokkiligadda Anusha, Vij Shilpa
Dairy Microbiology Division, National Dairy Research Institute, Karnal, 132001 India.
3 Biotech. 2017 Oct;7(5):349. doi: 10.1007/s13205-017-0985-1. Epub 2017 Sep 25.
The dairy yeast represents a promising industrial strain useful for the production of bioethanol from cheese whey. Physiology of the five strains on galactose was examined during batch cultivation under controlled aerobic conditions on minimal media and one of the strains designated strain 6C17 which presented the highest specific galactose consumption rate. A maximum specific growth rate of 0.34 and 0.37 h, respectively, was achieved using batch cultivation in a minimal medium and a complex medium amended with galactose (50 g/L) at 37 °C. The sugar was metabolized for the production of ethanol as the chief metabolite with a maximum ethanol yield of 0.39 g/g of galactose. Different growth behaviors were observed when galactose was used with other sugar such as glucose, lactose and fructose. The growth rates on hydrolyzed cheese whey were also measured, and a maximum specific growth rate of 0.39 and 0.32 h was observed with glucose and galactose, respectively, with the maximum flux diverted toward ethanol production. This approach of studying the physiology of thermotolerant on hydrolyzed whey during fermentation would be helpful in achieving higher yields of ethanol.
乳用酵母是一种很有前景的工业菌株，可用于从奶酪乳清中生产生物乙醇。在有氧条件下，于基本培养基上进行分批培养时，研究了五株菌株在半乳糖上的生理学特性，其中一株命名为6C17的菌株表现出最高的半乳糖比消耗率。在37℃下，使用添加了半乳糖（50 g/L）的基本培养基和复合培养基进行分批培养时，最大比生长速率分别达到0.34 h⁻¹和0.37 h⁻¹。糖被代谢用于生产乙醇作为主要代谢产物，最大乙醇产量为0.39 g/g半乳糖。当半乳糖与其他糖（如葡萄糖、乳糖和果糖）一起使用时，观察到不同的生长行为。还测量了在水解奶酪乳清上的生长速率，分别观察到葡萄糖和半乳糖的最大比生长速率为0.39 h⁻¹和0.32 h⁻¹，最大通量转向乙醇生产。这种在发酵过程中研究耐热菌在水解乳清上的生理学特性的方法，将有助于提高乙醇产量。
