RESEARCH ARTICLE Optimization of Various Parameters for Utilization of Apple Pomace Amended with Molasses by Indigenous Yeast Isolates Govind Kumar • Manvika Sahgal • Mahesh Kumar Bharti • Atindra K. Pandey • Anupama Singh Received: 8 April 2013 / Revised: 4 December 2013 / Accepted: 15 December 2013 / Published online: 12 November 2014 Ó The National Academy of Sciences, India 2014 Abstract In present study, yeast strains YGM1 and YGM2 were evaluated and the selected strain YGM1 was evaluated for its ethanol producing efficiency using varying substrate combinations. Both strain YGM1 and YGM2 were able to grow in wide range of temperature from 25 to 40 °C. Based on cfu ml -1 and corresponding absorbance values of two, YGM1 was rapid multiplier and better performer at 37 °C. During fermentation, pH of the sub- strate first decreased and then increased. Alcohol producing ability of YGM1 in substrates; 100 % pomace, 75 % pomace, 25 % molasses, 25 % pomace: 75 % molasses and 100 % molasses was compared. Alcohol producing ability is directly related to sugar utilization maximum amount of ethanol, 5.02 % was produced in pomace: molasses (75 %:25 %) and minimum 2.33 % in 100 % molasses. Maximum ethanol production, 5.02 % corresponded to maximum sugar utilization (11.31 %) in the 75 % pomace: 25 % molasses. Thus out of four combinations, 75 % pomace: 25 % molasses was better substrate for alcohol production. Keywords Apple pomace  Fermentation  Molasses  Indigenous  Invertase Introduction India is the ninth largest producer of apple in the world contributing an annual production of 1.42 MT (million tonnes) from an area of 0.25 million hectares [1]. During processing for juice about 75 % of the fresh weight of fruit is recovered as juice and 25 % as pomace [2, 3]. Apple pomace has high chemical oxygen demand (C.O.D) and high biological oxygen demand that is why it’s biode- gradable [4]. Production of ethanol when apple pomace is used as a substrate solely as it contains approximately 26.41 % dry matter, 17.35 % total sugar out of it 5–8 % is reducing sugar. It has been reported that production of ethanol increases at 16 % sugar concentration [5]. Several cellulosic substrates could be used to increase the sugar concentration of apple pomace. Molasses is one of them. It is a by-product of sugar industry and available in plenty at cheap price [6]. It’s reported that molasseses contain 51 % total reducing sugar out of which 45 % is fermentable and 5 % is non fermentable including hemicellulose, waxes and dextran [7]. Our main objective is optimizing various parameters for proper utilization of amended substrate by using effective yeast strain. G. Kumar  M. Sahgal Department of Microbiology, College of Basic Sciences and Humanities, College of Ag. and Tech, G. B. Pant University of Agriculture and Technology, U.S. Nagar, Pantnagar, Uttarakhand, India e-mail: govind34093@gmail.com M. K. Bharti (&) Department of Biochemistry, College of Basic Sciences and Humanities, College of Ag. and Tech, G. B. Pant University of Agriculture and Technology, U.S. Nagar, Pantnagar 263145, Uttarakhand, India e-mail: bharti_biochem@rediffmail.com A. K. Pandey Molecular Biology and Biotechnology Division, National Bureau of Fish Genetic Resources, Lucknow 226002, UP, India A. Singh Department of Post Harvest and Food Processing, College of Ag. and Tech, G. B. Pant University of Agriculture and Technology, U.S. Nagar, Pantnagar, Uttarakhand, India 123 Natl. Acad. Sci. Lett. (November–December 2014) 37(6):529–533 DOI 10.1007/s40009-014-0273-0