Food and Industrial Microbiology Unit, Department of Microbiology, Faculty of Biological Sciences, University of Calabar, Calabar, Nigeria.
Environmental Microbiology and Biotechnology Unit, Department of Microbiology, Faculty of Biological Sciences, University of Calabar, Calabar, Nigeria.
Prep Biochem Biotechnol. 2024 May;54(5):597-611. doi: 10.1080/10826068.2023.2259452. Epub 2023 Oct 3.
The biological conversion of agro-waste biomass into value-added metabolites is one of the trendy biotechnological research areas in recent times. One of the major drawbacks of the bioprocess is the saccharification potential of the amylolytic enzyme that releases reducing sugar from complex biomass to serve as substrate for fermentation. The present study reports the production of a novel tripartite raw starch-digesting amylase (RSDA) by an indigenous strain with α-, β-, and gluco-amylolytic activities and its potential for bioethanol production. Response surface statistics was employed to develop a suitable medium for improved production of the tripartite enzyme by submerged fermentation. The bioprocess selected raw starch (4.36%) Ca(2.71 g/L) and Zn (0.0177 g/L) as significant variables which demonstrated a total RSDA activity of 7208.23 U/mL in a 5-L batch bioreactor. SDS/Native-PAGE determined the molecular weights of the 27-fold purified product as 25.2 kDa, 57.3 kDa, and 90.1 kDa for α-, β-, and gluco-amylases, respectively. Optimum temperature and pH for enzyme activity were respectively broad at 30-70 °C and 4-11. The enzyme mixture demonstrated digestibility above 90% against a variety of raw starches and simultaneous fermentation of digestate with generated 71.69 g/L of bioethanol within 24 h suggesting great potential for bioethanologenesis.
农业废弃物生物质转化为增值代谢物是近年来生物技术研究的热门领域之一。生物过程的主要缺点之一是淀粉分解酶的糖化潜力，它从复杂的生物质中释放还原糖作为发酵的底物。本研究报告了一种新型的三元原淀粉消化淀粉酶（RSDA）的生产，该酶由一株具有α-、β-和葡萄糖淀粉酶活性的本土菌株产生，具有生物乙醇生产的潜力。响应面统计数据被用于开发合适的培养基，以通过浸没发酵提高三元酶的产量。生物过程选择原淀粉（4.36%）、Ca（2.71 g/L）和 Zn（0.0177 g/L）作为显著变量，在 5-L 分批生物反应器中总 RSDA 活性达到 7208.23 U/mL。SDS/Native-PAGE 确定 27 倍纯化产物的分子量分别为 25.2 kDa、57.3 kDa 和 90.1 kDa，分别为 α-、β-和葡萄糖淀粉酶。酶活性的最适温度和 pH 值分别在 30-70°C 和 4-11 之间较宽。该酶混合物对各种原淀粉的消化率超过 90%，同时对消化物进行发酵，生成 71.69 g/L 的生物乙醇，在 24 h 内，这表明生物乙醇生成具有很大的潜力。
