Some radiotrofik fungi melanin production and optimization

Microorganisms are exposed to different environmental conditions in nature. These are the physical stresses such as heat, pressure, electrical current, ultrasonic waves, light/radiation, and osmotic shock, the chemical stresses such as acids, salts and oxidizers, and the biological stresses such as microbial metabolites and competitive flora. Living beings can either lose their lives or maintain their lives in these stressful environments with their adaptation mechanisms. For many years, they have wondered how the microorganisms live in the extreme environments and their adaptation mechanisms that subsequently emerge in extremely stressful environments. Radiotrophic fungi have numerous remarkable features such as extreme endurance against heavy metals, oxidative damages, ultraviolet radiation, hot and cold stress, and drought. Owing to these features, studies on fungal melanin and bacteria have increased in recent years. In particular, intensive research studies have been conducted on the detoxification of heavy metals and xenobiotics that cause serious environmental problems. As a result of these studies, it is determined that the resistance mechanisms of the radiotrophic fungi against adverse environmental conditions are associated with melanin pigmentation that they produce. One of the most remarkable features of the melanin is that it can absorb all types of electromagnetic radiation. Melanin induces fungicide resistance as well as protecting fungi from lytic enzymes, extreme temperatures, and drought. However, the factors affecting the production of melanin in plant pathogens are very complex. Determination of the factors influencing the production of melanin by this plant pathogen fungi will allow it to be used as a potential biocontrol agent. For this purpose, the impacts of parameters such as initial pH, agitation speed, different mediums and temperature on melanin production of the Alternaria alternata, which is a radiotrophic fungus, were tested. The effect of melanin production was determined by adding H2O2 in different concentrations to the mediums in the predetermined optimum pH, agitation, and temperature range. As a result of this study, it was determined that, for the optimum melanin production of A. alternata, the most appropriate medium was PDB, the best temperature was 20 oC, the optimal pH was 4, and the most appropriate agitation condition was 200 rpm.