高产纤维素酶的拟康宁木霉菌株8985固态发酵条件优化

木霉是重要的产纤维素酶真菌,在其可利用性评价筛选过程中,获得了一株在实验室条件下高产纤维素酶的拟康宁木霉菌株8985。采用响应面法对8985产纤维素酶的固态发酵条件进行了研究,以滤纸酶活为响应值,通过Plackett-Burman设计对11个因素进行了筛选,包括温度、湿度、发酵时间、K₂HPO₄、(NH₄)₂SO₄、Tween-80、麸皮添加量、CaCl₂、MgSO₄、乳糖和pH;分析结果表明,影响产酶的3个关键因素分别为发酵时间、K₂HPO₄浓度和麸皮添加量。进而采用最陡爬坡试验逼近3个关键因素的最大响应区域,采用Box-Behnken设计建立数学模型,获得最佳产酶条件为：发酵5d、K₂HPO₄ 5.18g/L、麸皮添加量0.281g/g,滤纸酶活性可达7.00IU/g,与理论值7.03IU/g接近,是优化前的1.37倍,是菌株里氏木霉QM9414该酶活的2.92倍。研究结果为木霉菌种资源的利用提供了有价值的科学信息。

Optimization of solid state fermentation conditions for the high cellulase producing strain Trichoderma koningiopsis 8985

Many Trichoderma species are capable to produce cellulases. Trichoderma koningiopsis strain 8985 attracted our attention upon an extensive application capacity evaluation for cellulase producing strains of the genus. To optimize the culture conditions in solid state fermentation for strain 8985 to produce cellulase at a higher level, the Plackett-Burman experimental design was applied. Among eleven factors investigated, harvesting time, K₂HPO₄ concentration and wheat bran addition were found to be the key factors during the fermentation. The optimal concentration ranges of the three factors were examined by the steepest ascent path, and further determined according to the Box-Behnken design, which revealed as fermentation for 5 days with 5.18g/L K₂HPO₄ and 0.281g/g wheat bran, respectively. Under the optimal conditions, the maximum amount of FPase production reached 7.00IU/g of substrate, which approaches the theoretical value 7.03IU/g, is 1.37 times of that before optimization, and is 2.92 times of that by T. reesei strain QM9414. The results of this work provide useful information for potential application of cellulase producing fungi.