Enzymatic hydrolysis of banana stems (Musa acuminata): Optimization of process parameters and inhibition characterization

ABSTRACT

In current work, an optimum solid loading (solid: liquid = 1:20), pH (4.8), temperature (50°C), and enzyme dosing of 20 filter paper unit (amount of enzyme required to release 1 µmol of glucose as reducing sugar from filter paper in per mL per minute) were enumerated for enzymatic hydrolysis of banana stem using cellulase from Trichoderma reesei. Further, inhibition study on enzymatic hydrolysis of banana stem was investigated by the supplementation of monosaccharides (glucose, galactose, mannose, xylose, and arabinose), disaccharide (cellobiose), and inhibitors (acetic acid and furfural obtained from pre-enzymatic hydrolysis steps). Glucose and cellobiose showed inhibitory effect on enzymatic hydrolysis of pretreated banana stem at or above 8 g/L while galactose, mannose, and xylose showed a significant inhibitory effect at or above 4 g/L. Instead of inhibition, arabinose enhanced the enzymatic hydrolysis with increase in total reducing sugars. Acetic acid did not show any significant inhibition while furfural inhibited the system at a comparative low concentration of 2 g/L. Further, scanning electron microscopy analysis was performed to investigate the difference in ultra-structural morphology of raw biomass, pretreated biomass, and biomass obtained after enzymatic hydrolysis.

KEYWORDS:

• Banana stem
• enzymatic hydrolysis
• inhibitors
• lignocellulose
• regulation

Acknowledgments

Authors are thankful to scanning electron microscope at central research facility (CRF) of National Institute of Technology, Agartala. Dr. Tridib Kumar Bhowmick, Assistant Professor, Department of Bio Engineering, NIT Agartala, Tripura is also acknowledged for his assistance during SEM image analysis.

Disclosure statement

The authors indicate no potential conflicts of interest.

Additional information

Funding

Ministry of Human Resources and Development (MHRD) of Government of India is sincerely acknowledged for funding this research work through institute fund.