BioChem - DOS

Fed-batch production of green coconut hydrolysates for high-gravity second-generation bioethanol fermentation with cellulosic yeast

Bioresource technology : biomass, bioenergy, biowastes, conversion technologies, biotransformations, production technologies

Soares, Jimmy; Demeke, Mekonnen M.; Van de Velde, Miet; Foulquié -Moreno, Maria R.; Kerstens, Dorien; Sels, Bert F.; Verplaetse, Alex; Fernandes, Antonio Alberto Ribeiro; Thevelein, Johan M.; Fernandes, Patricia Machado Bueno

<P><B>Abstract</B></P> <P>The residual biomass obtained from the production of <I>Cocos nucifera</I> L. (coconut) is a potential source of feedstock for bioethanol production. Even though coconut hydrolysates for ethanol production have previously been obtained, high-solid loads to obtain high sugar and ethanol levels remain a challenge. We investigated the use of a fed-batch regime in the production of sugar-rich hydrolysates from the green coconut fruit and its mesocarp. Fermentation of the hydrolysates obtained from green coconut or its mesocarp, containing 8.4 and 9.7% (w/v) sugar, resulted in 3.8 and 4.3% (v/v) ethanol, respectively. However, green coconut hydrolysate showed a prolonged fermentation lag phase. The inhibitor profile suggested that fatty acids and acetic acid were the main fermentation inhibitors. Therefore, a fed-batch regime with mild alkaline pretreatment followed by saccharification, is presented as a strategy for fermentation of such challenging biomass hydrolysates, even though further improvement of yeast inhibitor tolerance is also needed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Green coconut hydrolysate production using an improved two-step fed-batch regime. </LI> <LI> Hydrolysates from coconut or its mesocarp containing up to 12% sugar were produced. </LI> <LI> Fermentation of coconut mesocarp hydrolysate resulted in 4.3% ethanol. </LI> <LI> Green coconut hydrolysate showed a prolonged fermentation lag phase. </LI> <LI> Fatty acids and acetic acid appear to be the main inhibitors in coconut. </LI> </UL> </P>

2017

Elsevier

publisher-specific-oa

0960-8524

244

1

pp.234-242

10.1016/j.biortech.2017.07.140

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART78540408

Coconut; Alkaline pretreatment; High-solid load; Advanced bioethanol; Non-detoxified hydrolysate; Mesocarp