Abstract:
Bioethanol from lignocellulosic biomass is a promising alternative to petroleum-based
fuels to alleviate greenhouse gas emissions and reduce the dependency on fossil
fuels. The lignocellulosic biomass is exploited for ethanol production due to its
sustainability and abundance. Sugarcane tops, an agricultural residue, was employed
in the present investigation to assess its potential as a feedstock for bioethanol
production by adopting different fermentation approaches, namely separate
fermentation, simultaneous saccharification and fermentation (SSF) and partially
consolidated bioprocessing (PCBP). The present study demonstrated the potential of
mono and co-fermentation for ethanol production. Comparison between separate
fermentation and SSF using S.cerevisiae showed the latter to be more efficient with
ethanol production of 5.69 % (v/v) in 30.67 h of fermentation time than separate
fermentation with 3.76 % (v/v) ethanol in 48 h. An integrated fermentation strategy
stated as partially consolidated bioprocessing (PCBP) was investigated to improve
fermentation efficiency. This process integrates simultaneous pretreatment and
saccharification (SPS), conducted by enzyme blends of laccase and cellulase followed
by co-fermentation using S. cerevisiae and xylose-fermenting yeast AKBR 212. This
approach resulted in a 7.57 % (v/v) maximum ethanol concentration in 24.30 h. The
different fermentation strategies involved enzymes and yeasts only, thus offering a
green biotechnology approach towards converting sugarcane tops into bioethanol.
