A sustainable approach of turning potato waste towards bioethanol production using indigenous microbes of Himachal Pradesh, India

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 highaltitude strain, B. amyloliquefaciens, shown promising starch hydrolysis (12.06 g/L reducing sugars) over acid hydrolysis and is capable of working at 30-50 degrees 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 nonlinear 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 degrees 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 starchhydrolyzing and fermentation capabilities to bioethanol biorefinery.

Automated summary

In this study, a high-altitude strain B. amyloliquefaciens was found to effectively convert potato peel waste into bioethanol, with a high ethanol yield. By optimizing the fermentation variables, Acinetobacter sp. was able to produce ethanol efficiently. This study not only evaluated the sustainability of microbial conversion of waste to energy and bioethanol production in the Himalayan region, but also introduced promising extremophilic microbial strains with starch-hydrolyzing and fermentation capabilities for bioethanol biorefinery.