An improved enzymatic pre-hydrolysis strategy for efficient bioconversion of industrial pulp and paper sludge waste to bioethanol using a semi-simultaneous saccharification and fermentation process
journal contributionposted on 14.04.2021, 15:17 by Pinaki Dey, Vivek Rangarajan, Jayato Nayak, Diganta DasDiganta Das, Steeve Branden Wood
The current study investigated an integrated fermentation process for efficient conversion of pulp and paper sludge (PPS) material to bio-ethanol. To achieve maximum yield of reducing sugar from the pretreated PPS, most influencing parameters such as enzyme dosages, surfactant dosages on PPS loadings were optimized in a batch saccharification process using response surface methodology. The experimental validation studies under optimal conditions of 6% (w/w) solid loading condition, 0.16 % (w/w) of surfactant concentration and 158 FPU/gm of enzyme 2 loading resulted in a maximum reducing sugar yield of 45 ± 3.75 % (w/w). Separate batch saccharification studies were conducted with 4% to 7% (w/w) solid loading to formulate best operating conditions for fed-batch saccharification with 13% (w/w), 18% (w/w) and 22% (w/w) high solid loading. The PPS solid loading of 18% (w/w) in fed-batch saccharification resulted in maximal release of glucose and xylose of 79.56 g/L and 8.65 g/L respectively at 60 h. Further improvement in the conversion of PPS to bioethanol was established through adoption of fed batch semi-simultaneous saccharification and co-fermentation (S-SSCF) process. Fermentation using co-cultivation of two yeast species namely P. stipitis NCIM 3499 and Baker’s yeast resulted in maximum ethanol concentration of 42.34 g/L with 0.53 g/g yield from 18 % (w/w) solid loading. Thus, the current study demonstrated the potential application of PPS waste as a feedstock material for ethanol production, which can be adopted by industries as an environment-friendly alternative to common solid waste management.
Short Term research Grant as financial support provided to the faculty members (Sanctioned Letter: KITS/AR/OR/73/2018, Sr no (1) from Karunya Institute of Technology and Sciences
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