Comparative Analysis of Mucor Indicus Against Aspergillus Niger and Aspergillus Fumigatus for Wheat Straw Fermentation to Produce Efficient, Inexpensive and Eco-Friendly Bioethanol

Abstract

Increasing fuel prices and depleting hydrocarbon resources have compelled scientists to accelerate their efforts in finding reliable petroleum alternatives. Bioethanol has emerged as one of the best solutions to fit in the situation. Therefore, this colorless, biodegradable, eco-friendly liquid by all means is capable of replacing petrol. Its unique characteristics appealed modern scientists to conduct researches in this dimension more seriously. Among various production ways, bioethanol can easily be produced by fermenting lignocellulosic materials through fungus. This study compared and analyzed its production by fermenting pretreated wheat straw using three fungi; Mucor indicus, Aspergillus niger and Aspergillus fumigates separately. At first, samples collected from soil (n=111) and rotten/decomposed vegetables (n=14) were grown on yeast extract peptone dextrose (YPD) agar at 370C for 5 days. From a total of 34 isolated colonies, three most abundant fungal species were selected and identified while others were left unknown. Morphological and microscopic characterization of these fungi was done by lacto-phenol cotton blue staining. To minimize limiting factors of production, fed batch process was opted for fungal fermentation of sugars. Bioethanol was extracted by rotary evaporator while estimation was done through colorimetric method. UV induced mutagenesis enhanced ethanol production potential of these isolates. For both wild and mutant isolates, this potential was compared and analyzed graphically. At 3% sugar concentration, bioethanol production from Mucor indicus, Aspergillus niger and Aspergillus fumigatus was optimum i.e. 8.2%, 6.1% and 6.4% respectively and it became 8.4% for Mucor indicus, 6.4% for Aspergillus niger and 6.4% for Aspergillus fumigatus after 15 minutes UV exposure. Hence, under same circumstances Mucor indicus, in comparison with other two strains came out as the most competent one to produce efficient bioethanol from wheat straw fermentation.