Sustainable fermentation approach for biogenic hydrogen productivity from delignified sugarcane bagasse

Abstract

Improper lignocellulosic wastes management causes severe environmental pollution and health damage. Conversion of such wastes particularly sugarcane bagasse (SCB) onto bioenergy is a sustainable approach due to a continuous depletion of conventional biofuels. The delignification of SCB is necessary to proceed for bio-genic H2 productivity by anaerobic bacteria. The effect of autoclaving, pre-acidification/autoclaving and pre-alkalization/autoclaving of SCB on glucose recovery and subsequently H2 productivity by dark fermentation was comprehensively investigated. Pre-acidified SCB with 1% H2SO4 (v/v) provided H2 productivity of 8.5 ± 0.14 L/kg SCB and maximum H2 production rate (Rm) of 105.9 ± 8.3 mL/h. Those values were dropped to 2.7 ± 0.13 L/kg SCB and 58.3 ± 12.9 mL/h for fermentation of delignified SCB with 2% H2SO4. This was linked to high levels of total phenolic compounds (1775.3 ± 212 mg/L) in the feedstock. Better H2 productivity of 13.9 ± 0.58 L/kg SCB and Rm of 133.9 ± 3.6 mL/h was achieved from fermentation of pre-alkalized SCB with 1%KOH (v/v). 256.8 ± 9.8 U/100 mL of α-amylase, 165.7 ± 7.6 U/100 mL of xylanase, 232.8 ± 6.1 U/100 mL of CM-Cellulase, 176.5 ± 5.0 U/100 mL of polyglacturanase and 0.702 ± 0.013 mg M B. reduced/min. of hydrogenase enzyme was accounted for the batches supplied with delignified SCB by KOH. The Clostridium and Bacillus spp. was dominance and prevalence resulting a higher H2 productivity and yield. A novel strain of Archea and alpha proteobacterium were also identified and detected.