Abstract

Although the management of citrus residues is of concern, their valorization is a challenging alternative. In this work, raw orange juice processing wastewater was spontaneously fermented to determine the succession in microbial communities and identify new indigenous microbial strains of high pectinolytic activity. Pectinolytic strains were isolated using citrus pectin as growth substrate. A shift in fungal population observed during spontaneous fermentation, where the abundances of Hanseniaspora, Cystofilobasidium and Meyerozyma were significantly increased, whereas Pichia fermentans followed by Saccharomyces spp. became the predominant taxa in the fermented wastewater. A significant reduction in the relative abundance of homofermentative aerococci and an increase in the relative abundance of heterofermentative leuconostocs and lactobacilli occurred during fermentation, while enterococci were predominant throughout the fermentation process. Regarding ecological indices, opposite changes took place in the bacterial compared to fungal community structure, but in a less pronounced degree. Examination of beta-diversity revealed the key role of Pichia species in driving fungal community structure during fermentation. P. fermentans, the predominant taxon in the fermented wastewater, was found to be the most effective pectinolytic microorganism. Pectin hydrolysis, carbohydrate fermentation to ethanol, lactic acid and acetate, and citric acid fermentation were the most important factors, influencing microbial community structure.

Graphic Abstract

中文翻译：

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橙汁加工废水中有效的土著果胶分解菌的微生物演替与鉴定

摘要

尽管对柑橘残渣的处理值得关注，但对其进行增值是一个具有挑战性的选择。在这项工作中，自发地发酵生橙汁加工废水，以确定微生物群落的演替，并确定具有高果胶分解活性的新的本地微生物菌株。使用柑橘果胶作为生长底物分离果胶分解菌株。在自发发酵过程中观察到真菌种群的变化，其中汉斯氏菌，胞嘧啶梭菌和肉毒杆菌的丰度显着增加，而发酵毕赤酵母随后是酵母菌spp。成为发酵废水中的主要分类单元。在发酵过程中，同型发酵球菌的相对丰度显着降低，异型发酵的隐球菌和乳酸杆菌的相对丰度增加，而肠球菌在整个发酵过程中占主导地位。关于生态指标，与真菌群落结构相比，细菌发生了相反的变化，但程度不明显。β多样性的检查揭示了毕赤酵母菌种在发酵过程中驱动真菌群落结构的关键作用。发酵单胞菌被发现是发酵废水中最主要的分类单元，是最有效的果胶分解微生物。果胶水解，碳水化合物发酵成乙醇，乳酸和乙酸盐以及柠檬酸发酵是影响微生物群落结构的最重要因素。

图形摘要