Department of Microbiology, University of Karachi, Karachi, Pakistan.
Department of Biosciences, Faculty of Life Sciences, Shaheed Zulfikar Ali Bhutto Institute of Science and Technology (SZABIST), Karachi, Pakistan.
Biotechnol J. 2023 Nov;18(11):e2200477. doi: 10.1002/biot.202200477. Epub 2023 Jul 26.
Halophytes are the native inhabitants of saline environment. Their biomass can be considered as a potential substrate for the production of microbial enzymes. This study was intended at feasible utilization of a halophytic biomass, Cressia cretica, for pectinase production using a halo- and thermo-tolerant bacterium, Bacillus vallismortis MH 10. The data from fractionation of the C. cretica biomass revealed presence of 17% pectin in this wild biomass. Seven different factors (temperature, agitation, pH, inoculum size, peptone concentration, substrate concentration, and incubation time) affecting pectinase production using C. cretica were assessed through a statistical tool, Plackett-Burman design. Consequently, two significant factors (incubation time and peptone concentration) were optimized using the central composite design. The strain produced 20 IU mL of pectinase after 24 h under optimized conditions. The enzyme production kinetics data also confirmed that 24 h is the most suitable cultivation period for pectinase production. Fourier transform infrared spectroscopy and scanning electron microscopy of C. cretica biomass ascertained utilization of pectin and structural changes after fermentation. The purification of pectinase by using DEAE column yielded specific activity and purification fold of 88.26 IU mg and 3.2, respectively. The purified pectinase had a molecular weight of >65 kDa. This study offers prospects of large-scale production of pectinase by halotolerant strain in the presence of economical and locally grown substrate that makes the enzyme valuable for various industrial operations.
盐生植物是盐环境的原生居民。它们的生物质可以被认为是微生物酶生产的潜在底物。本研究旨在利用盐生植物 Cressia cretica 生产果胶酶，使用耐盐和耐热细菌 Bacillus vallismortis MH 10。从 C. cretica 生物质的分级数据中发现，这种野生生物质中含有 17%的果胶。通过 Plackett-Burman 设计评估了影响使用 C. cretica 生产果胶酶的 7 个不同因素（温度、搅拌、pH 值、接种量、蛋白胨浓度、底物浓度和培养时间）。随后，使用中心复合设计优化了两个重要因素（培养时间和蛋白胨浓度）。在优化条件下，该菌株在 24 小时内产生 20 IU mL 的果胶酶。酶生产动力学数据也证实 24 小时是最适合果胶酶生产的培养期。C. cretica 生物质的傅里叶变换红外光谱和扫描电子显微镜证实了果胶的利用和发酵后的结构变化。使用 DEAE 柱对果胶酶进行纯化，得到 88.26 IU mg 的比活度和 3.2 的纯化倍数。纯化的果胶酶分子量大于 65 kDa。本研究为在经济且本地生长的底物存在下，利用耐盐菌株大规模生产果胶酶提供了前景，使该酶在各种工业操作中具有价值。
