Behera Swagatika, Dev Manoj J, Singhal Rekha S
Food Engineering and Technology Department, Institute of Chemical Technology, N. P. Marg, Matunga, Mumbai, 400 019, India.
Appl Biochem Biotechnol. 2022 May;194(5):1981-2004. doi: 10.1007/s12010-022-03807-w. Epub 2022 Jan 10.
β-Mannanase capable of hydrolyzing β-1,4-linkages in guar gum was immobilized as cross-linked enzyme aggregates (M-CLEAs). The aggregation and cross-linking process was optimized by response surface methodology (RSM) for maximum activity. The resulting M-CLEAs were characterized by FTIR, DSC, SEM, and SDS-PAGE. The M-CLEAs showed higher pH stability, improved thermal and storage stability, and reusability than free β-mannanase. For example, M-CLEAs were stable over broader pH range (5.5-8.5) with highest relative of activity of 98.17% at pH 6.5 and retained almost double activity than free mannanase at 50 °C after 4 h. Moreover, K and V of M-CLEAs were altered significantly, with a 1.5-fold increase and 0.98-fold decrease, respectively, than free β-mannanase. The prepared M-CLEAs could hydrolyze native guar gum (MW = 588,147 Da) to yield partially hydrolyzed guar gum (PHGG) (MW = 8023 Da).
能够水解瓜尔胶中β-1,4-键的β-甘露聚糖酶被固定化为交联酶聚集体（M-CLEAs）。通过响应面法（RSM）对聚集和交联过程进行优化以获得最大活性。通过傅里叶变换红外光谱（FTIR）、差示扫描量热法（DSC）、扫描电子显微镜（SEM）和十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）对所得的M-CLEAs进行表征。与游离β-甘露聚糖酶相比，M-CLEAs表现出更高的pH稳定性、更好的热稳定性和储存稳定性以及可重复使用性。例如，M-CLEAs在更宽的pH范围（5.5-8.5）内稳定，在pH 6.5时相对活性最高，为98.17%，并且在50℃下4小时后保留的活性几乎是游离甘露聚糖酶的两倍。此外，M-CLEAs的米氏常数（K）和最大反应速率（V）发生了显著变化，与游离β-甘露聚糖酶相比，K分别增加了1.5倍，V分别降低了0.98倍。制备的M-CLEAs可以水解天然瓜尔胶（分子量=588,147Da），得到部分水解瓜尔胶（PHGG）（分子量=8023Da）。
