Enzymatic and Acidic Hydrolysis of Cull Potatoes for Production of Fermentable Sugars

Cull potato is an under-utilized biomass being produced in different states of India. Using cull potatoes as a substrate for bioethanol production can overcome the post-harvest losses as well as making the process economical. In the present study, comparative hydrolysis of cull potatoes is carried out using enzymes and hydrochloric acid to study the effect of variables on saccharification efficiency. For enzymatic hydrolysis, samples are liquefied using crude enzyme from Bacillus sp. and then saccharification of liquefied samples is optimized using central composite rotatable design (CCRD) in Response surface methodology (RSM) w.r.t pH (4-7), temperature (25-40 degrees C) and incubation period (15-60 min) at 5% substrate concentration with glucoamylase of Aspergillus niger. Acidic hydrolysis is performed at different acid concentration, i.e., 1-5 (v/v) at variable time intervals (15-60 min) with 1-5% substrate concentration at 90 degrees C. Highest saccharification efficiency is observed with acidic hydrolysis 85.2% at substrate concentration of (4%) and at acid concentration (4% v/v) after 45 min of incubation, while with enzymatic hydrolysis it is very close to acidic hydrolysis, i.e., 83.2% at 25 degrees C temperature and at pH 4 after 30 min of incubation.