초록
<P><B>Abstract</B></P><P><B>Aims</B></P><P>Marine seaweeds (macroalgae) cause an eutrophication problem and affects the touristic activities. The success of the production of the third‐generation bioethanol from marine macroalgae depends mainly on the development of an ecofriendly and eco‐feasible pretreatment (i.e. hydrolysis) technique, a highly effective saccharification step and finally an efficient bioethanol fermentation step. Therefore, this study aimed to investigate the potentiality of different marine macroalgal strains, collected from Egyptian coasts, for bioethanol production via different saccharification processes.</P><P><B>Methods and Results</B></P><P>Different marine macroalgal strains, red <I>Jania rubens</I>, green <I>Ulva lactuca</I> and brown <I>Sargassum latifolium</I>, have been collected from Egyptian Mediterranean and Red Sea shores. Different hydrolysis processes were evaluated to maximize the extraction of fermentable sugars; thermochemical hydrolysis with diluted acids (HCl and H<SUB>2</SUB>SO<SUB>4</SUB>) and base (NaOH), hydrothermal hydrolysis followed by saccharification with different fungal strains and finally, thermochemical hydrolysis with diluted HCl, followed by fungal saccharification. The hydrothermal hydrolysis of <I>S. latifolium</I> followed by biological saccharification using <I>Trichoderma asperellum</I> RM1 produced maximum total sugars of 510 mg g<SUP>−1</SUP> macroalgal biomass. The integration of the hydrothermal and fungal hydrolyses of the macroalgal biomass with a separate batch fermentation of the produced sugars using two <I>Saccharomyces cerevisiae</I> strains, produced approximately 0·29 g bioethanol g<SUP>−1</SUP> total reducing sugars. A simulated regression modelling for the batch bioethanol fermentation was also performed.</P><P><B>Conclusions</B></P><P>This study supported the possibility of using seaweeds as a renewable source of bioethanol throughout a suggested integration of macroalgal biomass hydrothermal and fungal hydrolyses with a separate batch bioethanol fermentation process of the produced sugars.</P><P><B>Significance and Impact of the Study</B></P><P>The usage of marine macroalgae (i.e. seaweeds) as feedstock for bioethanol; an alternative and/or complimentary to petro‐fuel, would act as triple fact solution; bioremediation process for ecosystem, renewable energy source and economy savings.</P>