Screening of endophytic fungi from Antarctic mosses: Potential production for L-asparaginase free of glutaminase and urease activity

Abstract

Studies involving endophytic fungi aim to identify organisms inhabiting extreme and relatively unexplored environments, as these fungi possess unique characteristics and uncommon biochemical pathways that enable them to produce compounds with biotechnological potential. Among various enzymes, L-Asparaginase is employed in the treatment of Acute Lymphoblastic Leukemia. In this study, we identified endophytic fungi from Sanionia uncinata and Polytrichastrum alpinum collected on King George Island in Antarctica. The fungi were categorized into morphological groups based on their characteristics, molecularly identified, and assessed for L-Asparaginase (L-ASNase) enzyme production. Subsequently, production optimization was conducted. A total of 161 endophytes were isolated from 504 moss gametophytes, with 107 originating from P. alpinum and 54 from S. uncinata. These isolates were categorized into 31 morphotypes. Fungi exhibiting high enzyme production were identified molecularly. Among them, nine identified isolates belonged to the genera Aspergillus, Collariella, Diaporthe, Epicoccum, Peroneutypa, Xylaria, and Trametes. Three of these isolates were identified at the species level through multigene phylogeny, namely Epicoccum nigrum, Collariella virescens, and Peroneutypa scoparia. All 31 fungi were subjected to solid media testing for L-ASNase enzyme production, with 22 isolates demonstrating production capability, and 13 of them produced L-ASNase free from Urease and Glutaminase. The isolates displaying solid media production underwent further testing in liquid media, all of which exhibited enzyme production ranging from 0.75 to 1.29 U g^-1. Notably, the three fungi identified at the species level were the highest producers of the enzyme (1.29, 1.17, and 1.13 U g^-1). The production of these fungi was optimized using the Taguchi method, resulting in production values ranging from 0.687 to 2.461 U g^-1. In conclusion, our findings indicate that Antarctic moss endophytic fungi exhibit significant potential for the production of the anti-leukemic enzyme L-ASNase.

Keywords: Ascomycota; Bioprospection; Bryophyta; In vitro production; L-ASPAse.