Enzymatic Potential of Bacteria and Fungi Isolates from the Sewage Sludge Composting Process

The aim of this study was the isolation and characterisation of the fungi and bacteria during the composting process of sewage sludge under a semipermeable membrane system at full scale, in order to find isolates with enzymatic activities of biotechnological interest. A total of 40 fungi were isolat...

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Bibliographic Details
Main Authors: Tatiana Robledo-Mahón, Concepción Calvo, Elisabet Aranda
Format: Article
Language:English
Published: MDPI AG 2020-11-01
Series:Applied Sciences
Subjects:
Online Access:https://www.mdpi.com/2076-3417/10/21/7763
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Summary:The aim of this study was the isolation and characterisation of the fungi and bacteria during the composting process of sewage sludge under a semipermeable membrane system at full scale, in order to find isolates with enzymatic activities of biotechnological interest. A total of 40 fungi were isolated and enzymatically analysed. Fungal culture showed a predominance of members of Ascomycota and Basidiomycota division and some representatives of Mucoromycotina subdivision. Some noticeable fungi isolated during the mesophilic and thermophilic phase were <i>Aspergillus</i>, <i>Circinella,</i> and <i>Talaromyces</i>. During the maturation phase, some lignin modifying enzyme producers, like <i>Purpureocillium</i>, <i>Thielavia</i>, <i>Bjerkandera,</i> or <i>Dichotomyces</i>, were found. Within this group, <i>Thielavia</i> and <i>Bjerkandera</i> showed high activity with production of laccases and peroxidases. In the bacterial culturome, a total of 128 strains were selected and enzymatically analysed. Bacillales, Actinomycetales, Pseudomonadales, and Lactobacillales were the orders most represented in culture-bacteria. <i>Bacillus pumilus</i>, <i>B</i>. <i>stratosphericus</i>, <i>B</i>. <i>safensis,</i> and <i>Pseudomonas formosensis</i> were the species most efficient in enzyme production, particularly peroxidases, polyphenol oxidases ammonifying activity, and amylases. These results showed that sewage sludge composting piles could represent a source of microorganisms which have adapted to adverse conditions.
ISSN:2076-3417