Laboratory of Food Industrial Enzyme Technology, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, China.
R&D Center of Dongsheng Bio-TECH, Shanghai, China.
J Sci Food Agric. 2023 Jul;103(9):4562-4572. doi: 10.1002/jsfa.12535. Epub 2023 Mar 14.
Protein glutaminase (PG) is a novel protein modification biotechnology that is increasingly being used in the food industry. However, the current level of fermentation of PG-producing strains still does not meet the requirements of industrial production. To obtain the mutant strains with high PG production, the atmospheric and room temperature plasma (ARTP) combined with LiCl chemical mutagen were used in mutagenesis of a PG producing Chryseobacterium proteolyticum 1003.
A mutant strain (WG15) was successfully obtained based on malonic acid resistance screening after compound mutagenesis of the starting strain C. proteolyticum 1003 using ARTP with LiCl, and it was confirmed to be genetically stable in PG synthesis after 15 generations. The protein glutaminase production of WG15 was 2.91 U mL after optimization of fermentation conditions, which is 48.69% higher than the original strain C. proteolyticum 1003. The PG obtained from fermentation showed good activities in deamidation of soy protein isolate. The solubility and foaming properties of the PG-treated soy protein isolate were significantly increased by 36.50% and 10.03%, respectively, when PG was added at the amount of 100 U mL . In addition, the emulsifying activity and emulsion stability of the treated soy protein isolate were improved by 12.44% and 10.34%, respectively, on the addition of 10 U mL PG. The secondary structure of the soy protein isolate changed after PG treatment, with an increased proportion of glutamate.
The results of the present study indicate that the PG produced by this mutant strain could improve the functional properties of soybean protein isolate and the C. proteolyticum mutant WG15 has great potential in food industry. © 2023 Society of Chemical Industry.
蛋白谷氨酰胺酶（PG）是一种新型的蛋白质修饰生物技术，在食品工业中应用越来越广泛。然而，目前 PG 产生菌株的发酵水平仍不能满足工业生产的要求。为了获得具有高 PG 产量的突变株，采用大气压室温等离子体（ARTP）联合 LiCl 化学诱变剂对产 PG 的黄杆菌 1003 进行诱变。
通过 ARTP 联合 LiCl 对出发菌株 C. proteolyticum 1003 进行复合诱变，筛选出一株耐丙二酸的突变株（WG15），经 15 代遗传稳定性实验证明其在 PG 合成中具有遗传稳定性。优化发酵条件后，WG15 的蛋白谷氨酰胺酶产量为 2.91 U mL，比原始菌株 C. proteolyticum 1003 提高了 48.69%。发酵得到的 PG 对大豆分离蛋白的脱酰胺活性较好。当 PG 添加量为 100 U mL 时，PG 处理的大豆分离蛋白的溶解度和起泡性分别显著提高了 36.50%和 10.03%。此外，当添加 10 U mL PG 时，处理后的大豆分离蛋白的乳化活性和乳化稳定性分别提高了 12.44%和 10.34%。PG 处理后大豆分离蛋白的二级结构发生变化，谷氨酸的比例增加。
本研究结果表明，该突变株产生的 PG 可以改善大豆分离蛋白的功能特性，C. proteolyticum 突变株 WG15 在食品工业中有很大的应用潜力。© 2023 化学工业协会。
