Production of bioethanol from sweet lime peel via a statistically optimized simultaneous saccharification and fermentation process using isolated enzymes

ABSTRACT

The present study is to explore sweet lime peel and to investigate the possibility of isolation of enzymes for bioethanol production. Acid assisted steam pretreatment was employed for sweet lime peel as a pretreatment process in order to release more cellulose for hydrolysis. Cellulose content was increased from 25.4% to 34.8% by steam pretreatment. Cellulase and pectinase enzymes required for the hydrolysis of sweet lime peel were isolated from Aspergillus niger by solid-state fermentation. The activity of the in vitro produced cellulase and pectinase were 1.712 FPU/ml and 3.195 IU/ml, respectively. Simultaneous saccharification and fermentation of pretreated sweet lime peel was carried out using isolated cellulase and pectinase enzymes and Saccharomyces cerevisiae respectively. The optimization of process variables, time, pH and temperature on fermentation efficiency was also investigated using response surface methodology. The maximum fermentation efficiency of 71.73% was attained at pH 5°C and 37°C after 72 h of saccharification and fermentation.

KEYWORDS:

• Sweet lime peel
• cellulase
• pectinase
• bioethanol
• optimization

Additional information

Notes on contributors

Indulekha John

Indulekha John graduated B.Tech (BioTechnology) from University of Calicut, Kerala, India. She obtained her M.Tech (Energy Engineering) and Ph D from NIT Tiruchirappalli, Tamil Nadu. Her research work is on bioethanol production. To her credit, she has published 4 articles in the international journals and a book chapter.

Jishnu Pola

Jishnu Pola did his M Tech in Chemical Engineering at National Institute of Technology. He is working as  Energy Engineer from Nov 2017 at CII Green Business Centre, Hyderabad.

Karuppan Muthukumar

Karuppan Muthukumar started his teaching career in 2001 at A.C.Tech, Anna University, Chennai. He did his post-doctoral fellowship at Georgia Institute of Technology, Atlanta under Prof. Sankar Nair. He has published more than 60 international papers. His prime research work includes biorefinery engineering, biorefinery separations, and development of innovative methods for waste valorization.

Murugesan Thanabalan

Murugesan Thanabalan has 30 years of teaching experience. His area of interest includes Ionic liquids/ eutectic solvents for CO₂ capture, Gas separation, Utilization of biomass. He has received award for Best Teaching, Researcher in UTP. He has published (195) journals in national and international peer reviewed journals.

Arunagiri Appusamy

Arunagiri Appusamy started his teaching career in 2001 at A. C. College of Technology, Anna University. His area of Interest is mainly transfer operations, Energy & Environment. He has published 30 International Journals.