Potato peel waste is one of the zero-value wastes with the potential of bioethanol production through the Waste to Energy (WtE) approach. The newly isolated, phenotypically characterized, and molecular identified high-altitude strain, B. amyloliquefaciens, shown promising starch hydrolysis (12.06 g/L reducing sugars) over acid hydrolysis and is capable of working at 30-50 °C and pH 6.0-8.0. The ethanol production by Acinetobacter sp. (a newly isolated, phenotypically characterized, molecular identified) has been modelled and optimized through the central composite design of response surface methodology by taking the fermentation variables as input variables and ethanol yield as the output variable. The ethanol production by Acinetobacter sp. showcased a non-linear relationship of fermentation variables with the ethanol yield (5.83 g/L) with a 99.11% desirability function (R2) and 97.50 adj. R2 values. Optimal fermentation variables of 38.8% substrate concentration, 7% inoculum, pH 5.45 have been utilized for bioethanol production in 55.27 h at 27 °C. Overall, the present study evaluated the efficiency of newly isolated, indigenous extremophilic microbes of The Himalayan region in sustainable bioethanol production from zero-value waste "Potato peel waste" through the WtE approach. Moreover, the present study introduces the promising, unexplored extremophilic microbial strains with the starch-hydrolyzing and fermentation capabilities to bioethanol biorefinery.
Keywords: Acinetobacter sp.; Bioethanol; Enzymatic hydrolysis; High altitude; Potato waste; Thermotolerant.
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