ABSTRACT
This research was carried out to produce ethanol for use as a sanitizer in today's COVID-19 pandemic situation, via cost-effective and eco-friendly techniques. The waste of seasonal fruit, i.e. apple, grape and Indian blueberry, was used in the study. Saccharomyces cerevisiae (baker's yeast) was used with KMnO4 (5%), sucrose (47 g) and urea (1.5 g) for the fermentation process. All the selected overripe fruits were analyzed for variations in parameters including specific gravity, pH, temperature and concentration during complete fermentation for ethanol production. After complete fermentation, it was clear that the use of Indian blueberry at a temperature of 33 °C, specific gravity of 0.875 and pH value of 5.2 yielded the highest ethanol concentration of 6.5%. The concentration of ethanol obtained from grape samples was 5.23% at 30 °C with specific gravity of 0.839 and pH 4.3. Lastly, the ethanol concentration obtained from apple waste was about 4.52% at 32 °C with specific gravity of 0.880 and pH of 4.7 pH. The FTIR curve of each sample shows an absorbance peak in a wave number range of 3000 cm-1 to 3500 cm-1, which indicates the absence of alcohol in the samples after fermentation.
ABSTRACT
According to recent reports, the global market for melatonin is worth 700 million USD in 2018 and would reach 2,790 million USD by 2025, growing at a CAGR of 18.9% during 2019 to 2025. Having regard to the prevalence of sleep and circadian rhythm disorders and a clear tendency to increase the demand for melatonin, and the current lack of alternative green and cost-efficient technologies of its synthesis, the supply of this remedy will not be enough to guarantee melatonin supply and affordability on a global scale. The emergence of naturally occurring melatonin and its isomers in fermented foods has opened an exciting new research area; there are still, however, some obscure points in the efficient microbiological biosynthesis of melatonin. This review summarizes the research progress and recent evidence related to melatonin and its isomers in various foodstuffs. Additionally, one possible way to synthesize melatonin is also discussed. The evidence pointed out that the presence of melatonin and its isomers is not exclusive for grapes and grape-derived products, because it can be also found in sweet and sour cherries. However, different species of both Saccharomyces and non-Saccharomyces yeasts could be used to obtain melatonin and melatonin isomers in the process of alcoholic fermentation biotechnologically. The availability of L-tryptophan has been a key factor in determining the concentration of indolic compounds produced, and the utilization of probiotic lactic acid bacteria could help in the formation of melatonin isomers during malolactic fermentation. These approaches are environmentally friendly alternatives with a safer profile than conventional ones and could represent the future for sustainable industrial-scale melatonin production.