초록
<P><B>Abstract</B></P> <P>The study aimed to utilize the industrial spent seaweed biomass (SSB) for effective ethanol production using yeast as a fermenting microorganism. Pretreatment of SSB was optimized using different acids. The highest percentage of spent biomass was obtained from <I>G. corticata</I> (12.53 ± 2.66% DW). The proximate, ultimate and biochemical constituents of spent biomass were calculated. The total sugar (440 ± 40 mg/g DW), reducing sugar (129.85 ± 10.23 mg/g DW) and protein (11.08 ± 0.11 mg/g DW) content of SSB were analysed. Pretreatment was optimized using three different acids. The effect of different pH (4.5, 5.0, 5.5 and 6.0) and temperature (30 and 35 °C) on ethanol production using baker’s and MTCC yeast was studied. At 35 °C, the maximum (4.85% w/w) ethanol production was achieved in a fermentation process maintained at pH 4.5 and 5.0 at 24 h and 72 h, respectively. Substrate fermented with MTCC yeast recorded the maximum production of ethanol (4.98% w/w) at pH 4.5 within 48 h. The fermentation process was scaled up to 300 mL for ethanol production, and achieved 3.75% w/w ethanol (72 h, pH 5.5). To conclude, in future SSB would be a potential renewable novel substrate for bioethanol production when compared to other lignocellulosic substrates.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Spent seaweed biomass (SSB) from <I>Gracilaria</I> sp. utilized for ethanol production. </LI> <LI> Mild sulphuric acid pretreatment found better sugar yield. </LI> <LI> HMF inhibition was optimized and controlled. </LI> <LI> Ethanol yield of 4.98% (w/w) was obtained from SSB. </LI> <LI> Industrial SSB and drifted seaweeds disposed after ethanol production was proposed. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>