Rosgaard Lisa, Pedersen Sven, Cherry Joel R, Harris Paul, Meyer Anne S
Novozymes A/S, Krogshoejvej 36, Bagsvaerd, DK-2880 Denmark.
Biotechnol Prog. 2006 Mar-Apr;22(2):493-8. doi: 10.1021/bp050361o.
This study examined the cellulytic effects on steam-pretreated barley straw of cellulose-degrading enzyme systems from the five thermophilic fungi Chaetomium thermophilum, Thielavia terrestris, Thermoascus aurantiacus, Corynascus thermophilus, and Myceliophthora thermophila and from the mesophile Penicillum funiculosum. The catalytic glucose release was compared after treatments with each of the crude enzyme systems when added to a benchmark blend of a commercial cellulase product, Celluclast, derived from Trichoderma reesei and a beta-glucosidase, Novozym 188, from Aspergillus niger. The enzymatic treatments were evaluated in an experimental design template comprising a span of pH (3.5-6.5) and temperature (35-65 degrees C) reaction combinations. The addition to Celluclast + Novozym 188 of low dosages of the crude enzyme systems, corresponding to 10 wt % of the total enzyme protein load, increased the catalytic glucose yields significantly as compared to those obtained with the benchmark Celluclast + Novozyme 188 blend. A comparison of glucose yields obtained on steam-pretreated barley straw and microcrystalline cellulose, Avicel, indicated that the yield improvements were mainly due to the presence of highly active endoglucanase activity/activities in the experimental enzyme preparations. The data demonstrated the feasibility of boosting the widely studied T. reeseicellulase enzyme system with additional enzymatic activity to achieve faster lignocellulose degradation. We conclude that this supplementation strategy appears feasible as a first step in identifying truly promising fungal enzyme sources for fast development of improved, commercially viable, enzyme preparations for lignocellulose degradation.
本研究考察了嗜热真菌嗜热毛壳菌、土栖嗜热放线菌、橙色嗜热子囊菌、嗜热科里纳斯菌和嗜热毁丝霉以及中温真菌绳状青霉的纤维素降解酶系统对蒸汽预处理大麦秸秆的纤维素分解作用。将每种粗酶系统添加到由里氏木霉衍生的商业纤维素酶产品纤维素酶和黑曲霉的β-葡萄糖苷酶诺维信188组成的基准混合物中进行处理后，比较了催化葡萄糖释放量。在一个包含一系列pH值（3.5 - 6.5）和温度（35 - 65摄氏度）反应组合的实验设计模板中评估酶处理效果。与基准纤维素酶+诺维信188混合物相比，向纤维素酶+诺维信188中添加低剂量的粗酶系统（相当于总酶蛋白负载量的10 wt%）显著提高了催化葡萄糖产量。对蒸汽预处理大麦秸秆和微晶纤维素（微晶纤维素）上获得的葡萄糖产量进行比较表明，产量的提高主要归因于实验酶制剂中存在高活性的内切葡聚糖酶活性。数据证明了通过额外的酶活性增强广泛研究的里氏木霉纤维素酶系统以实现更快的木质纤维素降解的可行性。我们得出结论，作为第一步，这种补充策略似乎可行，有助于确定真正有前景的真菌酶来源，以便快速开发用于木质纤维素降解的改良的、具有商业可行性的酶制剂。
