Department of Biotechnology, K.S. Rangasamy College of Technology, Tiruchengode, 637 215 Namakkal District, Tamil Nadu, India.
Department of Biotechnology, Faculty of Engineering, Karpagam Academy of Higher Education, Coimbatore 641 021, Tamil Nadu, India.
J Biosci Bioeng. 2020 Dec;130(6):571-576. doi: 10.1016/j.jbiosc.2020.07.008. Epub 2020 Aug 6.
Microbial production of xylanase is gaining the commercial importance, due to its wide range of applications from paper and pulp to food and feed industries. Streptomyces geysiriensis was used for the production of extracellular xylanase from lignocellulosic substrates such as rice bran and saw dust, under solid-state fermentation. The influence of pH, temperature and incubation period for the maximum production of xylanase was investigated with 1:2 (w/v) of substrate to moisture ratio at 100 rpm shaking conditions. The maximum production was recorded after 5 days of fermentation with pH 8.0 at 40 °C. The scale-up was done based on the results of optimized parameters using 3 L Applikon autoclavable bioreactor with maximum yield of 186 U/ml after 4 days of fermentation. Extracellular xylanase was separated by partitioning in aqueous two-phase system consisting of 20% polyethylene glycol 6000 and 12% KHPO with maximum yield of 93.97%. The investigation of the effect of pH and temperature and its incubation time showed that xylanase was retained its activity in a pH range of 6.5-8.5, with thermal stability from 20 °C to 60 °C up to 180 min. The presence of metal ions was found to inhibit the activity of xylanase especially Cu and Zn. Xylanase was stable both at 4 °C and room temperature (35 °C) for 30 and 9 days respectively. The kinetic parameters K (0.48 mg/ml) and V (8.33 U/mg) were determined using birchwood xylan as substrate.
木聚糖酶的微生物生产因其在造纸和纸浆、食品和饲料等行业的广泛应用而具有商业重要性。嗜热链霉菌被用于从木质纤维素底物如米糠和锯末中生产胞外木聚糖酶，采用固态发酵。在 100rpm 摇床条件下，以底物与水分比为 1:2（w/v），研究了 pH、温度和培养时间对木聚糖酶最大产量的影响。在 pH8.0、40°C 下发酵 5 天后，产量达到最大值。根据优化参数的结果进行放大，在 3L 可高压灭菌的 Applikon 自动发酵罐中进行，发酵 4 天后最大产量为 186U/ml。胞外木聚糖酶通过分配在由 20%聚乙二醇 6000 和 12% KHPO 组成的双水相体系中进行分离，最大产率为 93.97%。研究了 pH、温度及其孵育时间对其活性的影响，结果表明木聚糖酶在 pH6.5-8.5 范围内保持活性，在 20-60°C 下具有热稳定性，可达 180min。发现金属离子存在会抑制木聚糖酶的活性，尤其是 Cu 和 Zn。木聚糖酶在 4°C 和室温（35°C）下分别稳定 30 天和 9 天。使用桦木木聚糖作为底物，测定了动力学参数 K（0.48mg/ml）和 V（8.33U/mg）。
