## 1 Introduction  
At present, the demand for enzymes is increasing in different industrial activities, such as chemistry, food, textiles, and pharmaceuticals. In particular, the food industry is continuously demanding enzymes for use in fermentation and other processes. \(\alpha\)-amylase is one such enzyme with high demand in starch-processing industries, such as those involved in the production of glucose syrups, bread, and alcoholic beverages, because it is used for the hydrolysis of starch into simple sugar components. In addition, \(\alpha\)-amylase is widely used as an additive for making soaps, detergents, and animal feeds, as well as in treating paper and textiles [1]. To be used on an industrial scale, the efficient and environmentally friendly production of enzymes is essential. Wild-type and genetically modified microorganisms have been considered good producers of food enzymes because those are more stable and steadily active, compared with plant and animal enzymes [2; 3; 4]. However, there are still many technical barriers that have to be overcome for the industrial-scale production of enzymes by microorganisms, such as low levels of enzyme production and secretion, contamination of enzymes with other components, and the instability of enzymes under certain conditions. Therefore, technology development is necessary to improve the efficiency of enzyme production and to ensure that the process is simple, fast, safe, and involves a low cost.  
Non-thermal atmospheric pressure plasma (NTAPP) is a cutting-edge technology that has been gaining attention for numerous applications, including environmental, medicinal, agricultural, decontamination, and food bioprocessing [5; 6; 7; 8]. Plasma, an ionized gas that is known as the fourth state of matter, can generate free electrons, neutral reactive oxygen and nitrogen species (RONS), charged gas ions, and active gas species [9]. Since RONS are known to produce deactivating and activating effects, depending on their concentration, plasma treatment can also possibly generate these dual effects based on the treatment dose. The application of NTAPP to microorganisms has been mostly focused on the deactivation of microbes harmful to human life [10; 11; 12]. In food industries, NTAPP has proven to be extremely useful for food preservation by mediating the deactivation of microorganisms, including pathogens, spoilage fungi, and bacterial spores [13]. The plasma-mediated activation of vitality and enzyme production in microorganisms has recently been reported in several studies [14; 15; 16; 17; 18]. Since a broad spectrum of plasma effects can be expected, depending on factors such as the types of microorganisms, dosage of plasma, and RONS produced, NTAPP is a potential technology that can be applied to improve enzyme production and the vitality of beneficial microorganisms. However, the fundamental processes involved in the effects of NTAPP on the activation of microbial cells are poorly understood.  
In a previous study, we observed that there was an increase in the germination and secretion of \(\alpha\)-amylase by _A. oryzae_ post plasma treatment [18]. As a continuous investigation, in the present study, we examined the effect of plasma on the germination, growth, and \(\alpha\)-amylase production in _A. oryzae_ by using a scaled-up sample size and NTAPP jet (NTAPP). _A. oryzae_, considered to be generally recognized as safe (GRAS), is a good model microbe for studying the production of food enzymes, because it is known to have the capability of producing and secreting high-value industrial enzymes [19; 20; 21].