Effects of Ultraviolet Exposure on the Tropical Fungi Aspergillus carbonarius and Aspergillus japonicus: Survival, Amylase Production, and Thermostability

Abstract

Background and Research Aims Although fundamental to tropical forest biodiversity, fungi have been largely neglected in conservation research. To examine the fungal response to increased ultraviolet C (UVC) radiation, we analyzed UVC radiation effects on the survival, growth, and amylase activity of Aspergillus carbonarius and Aspergillus japonicus. Methods A. carbonarius (strain URM 7305) and A. japonicus (URM 7270) were exposed to UVC (254 nm) for different periods, and morphological changes were compared to the control. Results Survival capacity and growth decreased after 10 min of exposure in A. carbonarius and after 25 min in A. japonicus. After 40 min, amylase activity decreased ( A. carbonarius: 35.8%; A. japonicus: 30.3%). Amylase thermostability at 60°C was lower in UVC-exposed strains (T50 15 min) compared to controls ( A. japonicus, 45 min; A. carbonarius, 30 min). However, the protein amount remained stable in all UVC-treated strains. Contamination by other fungi was observed in the UVC-exposed strains, confirming competitive strength loss in both species. This was not observed in the controls due to secondary metabolite production, which increased their competitive fitness. Conclusion We provide new information about UVC’s adverse effects on the survival and enzyme production of A. carbonarius and A. japonicus, which could mean a loss of species essential for proper soil functioning and biodiversity. Implications for conservation Experimental manipulation of biochemical and physiological reactions advances fungal conservation beyond distributional data. The experimental evidence supports previous studies, suggesting that the increased UV radiation caused by climate change may drastically affect fungal biochemistry and physiology.

An Environmentally Safe Production of Xylanases by Fusarium sp. EA 1.3.1 Using Agroindustrial Residues: Biochemical Characterization and Potential Applications

“…Transplanting was carried out periodically; the cultures were maintained at 30°C in a bacteriological oven for seven days and subsequently stored at 4°C. Fungi samples were also kept at 4 ºC on silica gel, according to previously publication [13].…”

Biochemical characterization of an acid‐thermostable glucoamylase from Aspergillus japonicus with potential application in the paper bio‐deinking

“…Previous studies have shown that Aspergillus japonicus is a good producer of different enzymes, such as pectinases, 9 ß‐fructofuranosidase, 10 ß‐glucosidase, 11 tannases, 12 phytases, 13 ß‐xylosidases 14 and amylases 15,16 . However, there are no reports in the literature about the biochemical characterization and the biotechnological application of the enzymes produced by this species.…”

“…8 Previous studies have shown that Aspergillus japonicus is a good producer of different enzymes, such as pectinases, 9 ß-fructofuranosidase, 10 ß-glucosidase, 11 tannases, 12 phytases, 13 ß-xylosidases 14 and amylases. 15,16 However, there are no reports in the literature about the biochemical characterization and the biotechnological application of the enzymes produced by this species. Thus, this work aimed to characterize the biochemical properties of the glucoamylase from A. japonicus and assess the potential application of this enzyme in recycled paper biobleaching.…”