Abena Tariku, Simachew Addis
Microbial Biotechnology Research Program, National Agricultural Biotechnology Research Center (NABRC), Ethiopian Institute of Agricultural Research, Ethiopia.
Institute of Biotechnology, Addis Ababa University, Ethiopia.
Heliyon. 2024 Aug 5;10(15):e35496. doi: 10.1016/j.heliyon.2024.e35496. eCollection 2024 Aug 15.
Xylanases (EC 3.2.1.8) catalyze the breakdown of xylan, which is the second most abundant polysaccharide in plant cell walls. Biological catalysts have gained greater global attention than chemical catalysts in different industrial processes because they are highly selective, easy to control and have a negligible environmental impact. The aim of this study was to investigate the xylanolytic potential of white-rot fungi, optimize their physicochemical conditions and characterize the resulting xylanase. Sixty-eight white-rot fungus (WRF) isolates were screened for their xylanolytic potential and growth conditions for maximal xylanase production using cheap agricultural residue (wheat straw) as the sole carbon source. Five WRF isolates with high xylanase yields (73.63 ± 0.0283-63.6 ± 0.01247 U/ml) were selected by qualitative and quantitative screening methods. The optimum xylanase production occurred at pH 5.0 and 28 °C. Solid-state fermentation (SSF) yielded a high amount of xylanase. The highest xylanase activity (80.9-61.274 U/mL) was recorded in the pH range of 5.0-6.5 and at 50 °C. The metal ions Mg, Ca and Mn enhanced the activity of xylanase (127.28-110.06 %), while Cu+, Fe and K inhibited the activity with 43.4-17 % losses. The km and Vmax were 0.32-0.545 mg/mL and 86.95-113.63 μmol/min/mg, respectively. This finding indicates that wheat straw can be used for large-scale xylanase production under SSF conditions. The pH and temperature profiles and stabilities indicate that the xylanase produced in the present study can be applied in food and animal feed industries.
木聚糖酶（EC 3.2.1.8）催化木聚糖的分解，木聚糖是植物细胞壁中含量第二丰富的多糖。在不同的工业过程中，生物催化剂比化学催化剂受到了更广泛的全球关注，因为它们具有高度选择性、易于控制且对环境的影响可忽略不计。本研究的目的是研究白腐真菌的木聚糖分解潜力，优化其物理化学条件，并对所得木聚糖酶进行表征。以廉价的农业残留物（麦秸）作为唯一碳源，筛选了68株白腐真菌（WRF）菌株的木聚糖分解潜力和最大木聚糖酶产量的生长条件。通过定性和定量筛选方法，选择了5株木聚糖酶产量高（73.63±0.0283 - 63.6±0.01247 U/ml）的WRF菌株。木聚糖酶的最佳产量出现在pH 5.0和28°C。固态发酵（SSF）产生了大量的木聚糖酶。在pH 5.0 - 6.5和50°C的范围内记录到最高木聚糖酶活性（80.9 - 61.274 U/mL）。金属离子Mg、Ca和Mn增强了木聚糖酶的活性（127.28 - 110.06%），而Cu+、Fe和K抑制了活性，损失率为43.4 - 17%。km和Vmax分别为0.32 - 0.545 mg/mL和86.95 - 113.63 μmol/min/mg。这一发现表明，在固态发酵条件下，麦秸可用于大规模生产木聚糖酶。pH和温度曲线及稳定性表明，本研究中产生的木聚糖酶可应用于食品和动物饲料工业。
