Influence of Non-Thermal Atmospheric Pressure Plasma Jet on Extracellular Activity of α-Amylase in Aspergillus oryzae

In a previous study, we found that plasma can enhance spore germination and alpha-amylase secretion in A. oryzae, a beneficial fungus used in fermentation. To confirm this, in the current study, we investigated the effects of plasma on development and alpha-amylase secretion using an enlarged sample size and a different plasma source: a plasma jet. There was a similar to 10% (p < 0.01) increase in spore germination upon non-thermal atmospheric pressure plasma jet (NTAPPJ) treatment for 5 min and 10 min, as compared with the control (no plasma treatment). The activity of alpha-amylase detected in potato dextrose broth (PDB) media during incubation was significantly elevated in plasma-treated samples, with a more obvious increase upon 10 min and 15 min treatments and 24-96 h incubation periods. The levels of the oxidation reduction potential (ORP) and NOX (nitrogen oxide species) were higher in the plasma-treated samples than in the control samples, suggesting that these two variables could serve as standard indicators for enhancing alpha-amylase activity after plasma treatment. Genome sequencing analysis showed approximately 0.0016-0.0017% variations (changes in 596-655 base pairs out of a total of 37,912,014 base pairs) in the genomic DNA sequence of A. oryzae after plasma treatment. Our results suggest that NATPPJ can enhance the spore germination and extracellular activity of alpha-amylase, probably by increasing the levels of ORP and NOX to an optimum level.

Automated summary

The study demonstrated that plasma treatment significantly increased spore germination and alpha-amylase activity in A. oryzae, likely by elevating levels of ORP and NOX. Genomic sequencing analysis showed minimal variations in the DNA sequence post plasma treatment, suggesting potential mechanisms for enhancing enzyme activity.