Akishev Zhiger, Aktayeva Saniya, Kiribayeva Assel, Abdullayeva Aliya, Baltin Kairat, Mussakhmetov Arman, Tursunbekova Annelya, Ramankulov Yerlan, Khassenov Bekbolat
National Center for Biotechnology, 13/5 Korgalzhyn Road, Nur-Sultan 010000, Kazakhstan.
Faculty of natural sciences, L.N.Gumilyev Eurasian National University, 2 Kanysh Satpayev Street, Nur-Sultan 010008, Kazakhstan.
Biology (Basel). 2022 Oct 22;11(11):1545. doi: 10.3390/biology11111545.
In the cheese-making industry, commonly chymosin is used as the main milk-clotting enzyme. Bactrian camel () chymosin (BacChym) has a milk-clotting activity higher than that of calf chymosin for cow's, goat's, ewes', mare's and camel's milk. A procedure for obtaining milk-clotting reagent based on recombinant camel chymosin is proposed here. Submerged fermentation by a recombinant yeast ( GS115/pGAPZαA/ProchymCB) was implemented in a 50 L bioreactor, and the recombinant camel chymosin was prepared successfully. The activity of BacChym in yeast culture was 174.5 U/mL. The chymosin was concentrated 5.6-fold by cross-flow ultrafiltration and was purified by ion exchange chromatography. The activity of the purified BacChym was 4700 U/mL. By sublimation-drying with casein peptone, the BacChym powder was obtained with an activity of 36,000 U/g. By means of this chymosin, cheese was prepared from cow's, goat's, ewes', camel's and mare's milk with a yield of 18%, 17.3%, 15.9%, 10.4% and 3%, respectively. Thus, the proposed procedure for obtaining a milk-clotting reagent based on BacChym via submerged fermentation by a recombinant yeast has some prospects for biotechnological applications. BacChym could be a prospective milk-clotting enzyme for different types of milk and their mixtures.
在奶酪制作行业，通常使用凝乳酶作为主要的牛奶凝固酶。双峰驼（）凝乳酶（BacChym）对牛奶、羊奶、马奶和骆驼奶的凝乳活性高于小牛凝乳酶。本文提出了一种基于重组骆驼凝乳酶制备牛奶凝固剂的方法。在50 L生物反应器中采用重组酵母（GS115/pGAPZαA/ProchymCB）进行深层发酵，成功制备了重组骆驼凝乳酶。酵母培养物中BacChym的活性为174.5 U/mL。通过错流超滤将凝乳酶浓缩5.6倍，并通过离子交换色谱进行纯化。纯化后的BacChym活性为4700 U/mL。通过与酪蛋白胨进行升华干燥，获得了活性为36,000 U/g的BacChym粉末。利用这种凝乳酶，分别从牛奶、羊奶、马奶和骆驼奶中制备奶酪，产率分别为18%、17.3%、15.9%、10.4%和3%。因此，所提出的通过重组酵母深层发酵基于BacChym制备牛奶凝固剂的方法在生物技术应用方面具有一定前景。BacChym可能是一种适用于不同类型牛奶及其混合物的有前景的牛奶凝固酶。
