Data_Sheet_1_How Carbon Source and Degree of Oligosaccharide Polymerization Affect Production of Cellulase-Degrading Enzymes by Fusarium oxysporum f. sp. lycopersici.docx

Cellulases are a group of enzymes responsible for the degradation of cellulose, which is one of the most abundant polymers on Earth. The three main groups of cellulases are endoglucosidases, exoglucosidases, and β-glucosidases; however, the mechanism of induction of these enzymes remains poorly characterized. Cellooligosaccharides are among the main inducers of these enzymes in filamentous fungi, yet it is not clear how their degree of polymerization may affect the strength of induction. In the present study, we investigated the effect of different carbohydrate-based inducers, such as lactose, sophorose, cellooligosaccharides, and xylooligosacharides, characterized by different concentrations and degree of polymerization, on cellulases production by the fungus Fusarium oxysporum f. sp. lycopersici, which is one of the most studied lignocellulose degrading fungi with the ability to consume both cellulose and hemicellulose. Moreover, the effect of carbon source on cellulase induction was assessed by growing the biomass on sucrose or glycerol. Results showed a correlation between induction efficiency and the cellooligosaccharides’ concentration and size, as well as the carbon source available. Specifically, cellotetraose was a better inducer when sucrose was the carbon source, while cellobiose yielded a better result on glycerol. These findings can help optimize industrial cellulase production.

纤维素酶（Cellulases）是一类负责降解纤维素的酶类，而纤维素是地球上储量最为丰富的聚合物之一。纤维素酶主要分为内切葡聚糖酶、外切葡聚糖酶与β-葡萄糖苷酶三大类，但目前对这类酶的诱导调控机制仍未得到充分表征。纤维寡糖（Cellooligosaccharides）是丝状真菌中这类酶的主要诱导物之一，但尚不明确其聚合度如何影响诱导强度。本研究以尖孢镰刀菌番茄专化型（*Fusarium oxysporum* f. sp. *lycopersici*）为研究对象——该菌是研究最为深入的木质纤维素降解真菌之一，兼具降解纤维素与半纤维素的能力——探究了不同浓度、不同聚合度的碳水化合物类诱导物（如乳糖、槐糖、纤维寡糖与木寡糖）对其产纤维素酶的影响。此外，本研究还通过以蔗糖或甘油为碳源培养菌体，评估了碳源对纤维素酶诱导的调控作用。研究结果显示，诱导效率与纤维寡糖的浓度、聚合度，以及所使用的碳源均存在相关性。具体而言，纤维四糖（Cellotetraose）在以蔗糖为碳源时表现出更优的诱导效果，而纤维二糖（Cellobiose）在以甘油为碳源时诱导效果更佳。本研究结果可为工业化纤维素酶生产的工艺优化提供理论参考。