The pulp of açaí palm fruits (Euterpe oleracea Mart.) is a valuable export commodity in Brazil. Its production generates 1.6 million tons/year of açaí seeds, a resource largely wasted. The seeds consist mainly of linear β-mannan, offering potential for prebiotic β-mannan-derived oligomers and mannose production. However, the crystalline structures of β-mannan hinder enzymatic hydrolysis. This study aimed to discover and characterize fungal enzymes targeting açaí seed β-mannan using a palm β-mannanase (EgMan5A) as a guide. Recombinant expression, enzyme optimization, kinetics, substrate specificity, and structural modeling were performed. The two fungal enzymes, JaMan5A and SlMan5A, were found to be specific for unsubstituted mannan, showing no activity toward galacto- and glucomannan. Among them, SlMan5A showed the highest activity on açaí seed β-mannan (∼24 U/mg) and other unsubstituted mannan substrates, likely due to its greater thermal robustness. These results provide valuable insights into β-mannan specificity contributing to the sustainable valorization of açaí seeds.

中文翻译：

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甘露聚糖特化 GH5 内切-1,4-β-甘露聚糖酶的发现和表征：阿萨伊 （Euterpe oleracea Mart.） 的策略种子升级


巴西莓棕榈果肉 （Euterpe oleracea Mart.） 是巴西有价值的出口商品。它的生产每年产生 160 万吨巴西莓种子，这种资源在很大程度上被浪费了。种子主要由线性 β-甘露聚糖组成，为益生元 β-甘露聚糖衍生的低聚物和甘露糖生产提供了潜力。然而，β-甘露聚糖的晶体结构阻碍了酶水解。本研究旨在以棕榈β-甘露聚糖酶 （EgMan5A） 为指导，发现和表征靶向巴西莓种子 β-甘露聚糖的真菌酶。进行重组表达、酶优化、动力学、底物特异性和结构建模。发现两种真菌酶 JaMan5A 和 SlMan5A 对未取代的甘露聚糖具有特异性，对半乳糖和葡甘露聚糖没有活性。其中，SlMan5A 对巴西莓种子 β-甘露聚糖 （∼24 U/mg） 和其他未取代的甘露聚糖底物表现出最高的活性，这可能是由于其更高的热稳健性。这些结果为β-甘露聚糖特异性提供了有价值的见解，有助于阿薩菜种子的可持续增值。