Department of Microbiology, Dr. Ikram-ul-Haq Institute of Industrial Biotechnology (IIIB), GC University Lahore, Lahore, 54000, Pakistan.
Depatment of Zoology, Dr. Nazir Ahmed Institute of Biological Sciences, GC University, Lahore, 54000, Pakistan.
BMC Biotechnol. 2024 Sep 27;24(1):69. doi: 10.1186/s12896-024-00895-w.
The present study deals with the production of cellulase-free endoxylanase by Aspergillus niger ISL-9 using wheat bran as a solid substrate. Endoxylanase was produced under a solid-state fermentation. Various growth parameters were optimized for the improved production of the enzyme. The Substrate level of 15 g was optimized as it provided the fungus with balanced aeration and nutrition. Among the six moisture contents investigated, Moisture Content 5 (MC5) was optimized (g/l: malt extract, 10; (NH)HPO, 2.5; urea, 1.0) and 10 mL of MC5 was found to give the highest production of endoxylanase. The pH and time of incubation were optimized to 6.2 and 48 h respectively. The Inoculum size of 2 mL (1.4 × 10 spores/mL) gave the maximum enzyme production. After optimization of these growth parameters, a significantly high endoxylanase activity of 21.87 U/g was achieved. Very negligible Carboxymethylcellulase (CMCase) activity was observed indicating the production of cellulase-free endoxylanase. The notable finding is that the endoxylanase activity was increased by 1.4-fold under optimized conditions (p ≤ 0.05). The overall comparison of kinetic parameters for enhanced production of endoxylanase by A. niger ISL-9 under Solid State Fermentation (SSF) was also studied. Different kinetic variables which included specific growth rate, product yield coefficients, volumetric rates and specific rates were observed at 48, 72 and 96 h incubation time and were compared for MC1 and MC5. Among the kinetic parameters, the most significant result was obtained with volumetric rate constant for product formation (Q) that was found to be optimum (1.89 U/h) at 72 h incubation period and a high value of Q i.e.1.68 U/h was also observed at 48 h incubation period. Thus, the study demonstrates a cost-effective and environmentally sustainable process for xylanase production and exhibits scope towards successful industrial applications.
本研究利用黑曲霉 ISL-9 以麦麸为固体基质生产无纤维素内切木聚糖酶。在固态发酵下生产内切木聚糖酶。优化了各种生长参数以提高酶的产量。底物水平优化为 15g，因为它为真菌提供了平衡的通气和营养。在所研究的六种水分含量中，优化了水分含量 5（MC5）（g/L：麦芽提取物 10；（NH 4 ）2 HPO 4 2.5；尿素 1.0），发现 10mL 的 MC5 可获得最高产量的内切木聚糖酶。优化了 pH 值和孵育时间分别为 6.2 和 48h。接种量为 2mL（1.4×10 个孢子/mL）可获得最大的酶产量。优化这些生长参数后，内切木聚糖酶的活性达到 21.87U/g。观察到非常低的羧甲基纤维素酶（CMCase）活性，表明产生了无纤维素内切木聚糖酶。值得注意的是，在优化条件下，内切木聚糖酶活性提高了 1.4 倍（p≤0.05）。还研究了固态发酵（SSF）下黑曲霉 ISL-9 生产内切木聚糖酶的增强生产的动力学参数的总体比较。在 48、72 和 96h 孵育时间下观察到不同的动力学变量，包括比生长速率、产物产率系数、容积速率和比速率，并将其与 MC1 和 MC5 进行比较。在动力学参数中，获得了产物形成的容积速率常数（Q）的最佳结果，在 72h 孵育期内发现 Q 为最优（1.89U/h），在 48h 孵育期内也观察到 Q 值较高（1.68U/h）。因此，该研究展示了一种具有成本效益和环境可持续性的木聚糖酶生产方法，并展示了在成功的工业应用方面的潜力。
