Rhizopus oryzae is a filamentous fungi reported as a postharvest pathogen in recent years. Ethanol treatment (0, 10, 20, and 30%) and UVC irradiation (0, 1, 2, 5, 10 minutes) were used both individually and in combination for the inactivation of Rhizopus oryzae spores. Survival ratio of the spores and LD50 values for ethanol and UVC irradiation were determined to quantify the germicidal effect. UVC exposure is found to be significantly more effective than ethanol treatment on the reduction of R. oryzae spore survivability. The combination of UVC exposure and ethanol treatment enhanced the lethality of applying each treatment separately and the enhancement increased as the UVC exposure time and ethanol concentrations increased. The lowest spore survival ratio was 0.015%, obtained after 30% ethanol treatment followed by 10 minute of UVC exposure. These observations suggest that ethanol treatment and UVC exposure can effectively be used as a possible strategy to inactivate R. oryzae spores.

In this study, microalgae culture (Chlorella vulgaris) and mint seedlings (Mentha spp.) were combined in a hydroponic system to improve plant growth. Mint seedlings were grown both in microalgae-containing and in microalgae-free trial groups, and both groups were subjected to aerated and non-aerated conditions to show the effect of aeration and microalgae co-cultivation on the mint weight and height. The plant quality was also determined with color measurements of the mint leaves. The increase in the weight of the plants was the highest in microalgae-containing and aerated group (0.47 g) and the lowest in microalgae-free and non-aerated group (0.22 g). On the other hand, the variation in the plant height was not significant between the groups, the growth was lateral. The best quality mint leaves were also produced in microalgae-containing and aerated group. Our results have revealed the symbiotic life of the mint plant placed in the hydroponic system with microalgae and demonstrated improved mint growth and quality. This co-cultivation system is also potentially more environmentally friendly compared to growing microalgae and mint independently because of lower cost of aeration and mixing for microalgae cultivation, higher nutrient consumption efficiency, and reduced nutrient outflow.

Rhizopus group organisms produce a variety of fermented foods and industrial products including enzymes, organic acids, lipid derivatives, pesticides, herbicides, antibiotics. Some strains of Rhizopus are good lactic acid producers, with many advantages over lactic acid producing bacteria. Lactic acid has a wide range of application in food processing industry. In this study, growth and lactic acid production of Rhizopus oryzae in response to different NaCl and KCl concentrations in the culture were investigated. The growth and lactic acid production depended on the salt concentration, they decreased as the salt concentration increased. The type of salt did not result in significant differences in terms of growth and lactic acid production.

Potato peel waste (PPW), a zero-value byproduct generated from potato processing, is a promising fermentation substrate due to its large quantity of starch, non-starch polysaccharide, lignin, protein, and lipid. Rhizopus oryzae is a filamentous fungus that is mainly known as a lactic acid producer and can ferment various agro-wastes. This study aimed to use R. oryzae for the fermentation of PPW. A series of batch fermentations were conducted to investigate the effects of different PPW loading rates (2 – 8%) and particle sizes (0 – 4mm). Under an initial PPW loading rate of 8% and particle size of 1 – 2mm, the maximum ethanol (23.9 mL/L) and lactic acid (2.60 mL/L) concentrations, the highest ethanol (11.93 mL/L•day) and lactic acid (1.56 mL/L•day) maximum production rates were obtained. Under these conditions, the yield of ethanol and lactic acid were 298 mL/mgPPW and 33 mL/mgPPW, respectively. R. oryzae was shown to utilize PPW as a substrate to produce value-added bioproducts such as ethanol (major product) and lactic acid.