Bioethanol from <em>Parthenium Hysterophorus</em> Substrate by <em>Saccharomyces cerevisiae</em>

This study was aimed to determine the efficient part of the Parthenium hysterophorus plant as a substrate for bioethanol production and optimize fermentation conditions to enhance the yield. When different parts of Parthenium hysterophorus such as stem, leaves, roots, inflorescence, and whole plant were used as the substrate with Saccharomyces cerevisiae, significantly higher quantities of bioethanol were produced with whole plant and leaves (1% V/V) than the other plant parts chosen. The entire plant was chosen as a substrate for bioethanol production to address its noxious weed status and simultaneously achieving economically efficient output, making its removal from agricultural land for economic gain. Fermentation conditions were optimized sequentially, changing one factor at a time while keeping other variables constant. The sequence of optimization is time of fermentation, amount of substrate, amount of yeast inoculum, pH of the media and the solution: air space ratio. The optimized fermentation time with the whole plant of Parthenium hysterophorus resulted in a 3 times higher ethanol yield on the 4th day of fermentation. When 12.5 g/100 mL amount of whole Parthenium hysterophorus plant substrate was used, the ethanol yield was significantly increased by 7.3 times, while using 5 g/100 mL of yeast inoculum resulted in a significantly higher yield. The pH of the media was optimized to 4.8, and the solution: air space ratio was optimized to 1:1.3 bioethanol output was significantly increased by 10 times. After optimizing all culture conditions, the bioethanol yield from the whole plant Parthenium hysterophorus substrate was significantly increased (10 times) than the non-optimized conditions.