纤维素是各种可持续工业产品的主要可再生资源。然而,对于它的利用,寻找新的有效酶对植物细胞壁解聚至关重要。除了微生物来源,纤维素酶也存在于植物中,然而,研究较少。肉质果实成熟包括细胞壁酶水解,导致组织软化。因此,越橘(越橘),产生经过广泛而快速软化的小水果,选择探索植物来源的纤维素酶。我们从最近测序的越莓基因组中鉴定出20个糖苷水解酶家族9(GH9)纤维素酶,其中四个显示出果实成熟特异性表达,并且可能与基于系统发育的果实软化有关,转录组和基因表达分析。这四种纤维素酶是分泌的酶:具有碳水化合物结合模块49的两种B型和两种C型。对于功能表征,这四种纤维素酶在巴斯德毕赤酵母中表达。所有重组酶都显示了对纤维素和半纤维素底物的葡聚糖酶活性。特别是,VmGH9C1表现出高活性和降解纤维素的能力,木葡聚糖,和葡甘露聚糖.此外,所有酶在宽pH(6-10)和温度范围(最佳70°C)下保持活性,揭示了植物GH9纤维素酶在木质纤维素工业生物加工中的潜在应用。
Cellulose is a major renewable resource for a wide variety of sustainable industrial products. However, for its utilization, finding new efficient enzymes for plant cell wall depolymerization is crucial. In addition to microbial sources,
cellulases also exist in plants, however, are less studied. Fleshy fruit ripening includes enzymatic cell wall hydrolysis, leading to tissue softening. Therefore, bilberry (Vaccinium myrtillus L.), which produces small fruits that undergo extensive and rapid softening, was selected to explore
cellulases of plant origin. We identified 20 glycoside hydrolase family 9 (GH9)
cellulases from a recently sequenced bilberry genome, including four of which showed fruit ripening-specific expression and could be associated with fruit softening based on phylogenetic, transcriptomic and gene expression analyses. These four
cellulases were secreted enzymes: two B-types and two C-types with a carbohydrate binding module 49. For functional characterization, these four
cellulases were expressed in Pichia pastoris. All recombinant enzymes demonstrated glucanase activity toward cellulose and hemicellulose substrates. Particularly, VmGH9C1 demonstrated high activity and ability to degrade cellulose, xyloglucan, and glucomannan. In addition, all the enzymes retained activity under wide pH (6-10) and temperature ranges (optimum 70 °C), revealing the potential applications of plant GH9 cellulases in the industrial bioprocessing of lignocellulose.