초록
<P><B>Abstract</B></P> <P>An innovative integrated biorefinery approach using the green macroalgae <I>Chaetomorpha linum</I> was investigated in the present study for the co-production of bioethanol and biogas. Among three pretreatments of <I>C. linum</I> biomass, consisting of acidic, neutral and alkali ones, 3% NaOH pretreatment gave the best result in terms of thallus disintegration, biomass recovery and enzymatic digestibility as demonstrated by scanning electron microscopy and saccharification tests. The hydrolysis of <I>C. linum</I> feedstock with a crude specific enzyme preparation, locally produced from fermentation of <I>Aspergillus awamori</I>, at 45°C, pH 5 for 30h gave the maximum yield of fermentable sugar of 0.22±0.02g/g dry substrate. An ethanol yield of 0.41g/g reducing sugar corresponding to about 0.093g/g pretreated algae was obtained after alcoholic fermentation by <I>Saccharomyces cerevisiae</I>. In the integrated proposed process, mycelium issued from the fungal fermentation, liquid issued from alkali pretreatment, residual from the non-hydrolysable biomass and all effluents and co-products represent a heterogeneous substrate that feed an anaerobic digester for biogas production. GC-analysis of this later showed that the biomethane yield reached 0.26±0.045L/gVS. This study presents therefore an eco-friendly biorefining process, which efficiently coproduce bioethanol and biomethane and generate only a single waste (0.3±0.01g/g) allowing an almost complete conversion of the algal biomass.</P> <P><B>Highlights</B></P> <P> <UL> <LI> <I>Chaetomorpha linum</I> was used as sustainable feedstock for co-production of bioethanol and biomethane. </LI> <LI> An eco-friendly process was developed, only generating 0.3±0.01g/g of waste. </LI> <LI> Ethanol yield obtained was 0.41g/g reducing sugar. </LI> <LI> Methane yield obtained was 0.26±0.045L/gVS. </LI> </UL> </P>