This study evaluates the production of biodiesel and ethanol from spent coffee grounds (SCG). The extraction of oil from SCG, biodiesel production and ethanol production processes were studied. The liquid-to-solid ratio and temperature were evaluated in the ultrasound-assisted extraction of the oil from SCG. The highest yield (12%) was obtained using 4 mL g1 liquid-to-solid ratio at 60 C for 45 min. The process to produce biodiesel showed a yield of 97% into fatty acid methyl esters (FAME). The highest glucose yield (192 mg gSCG1 ) was obtained by hydrolysis with 0.4 mol L1 sulfuric acid at 121 C for 15 min.
The hydrolysate was used as fermentation medium for ethanol production by Saccharomyces cerevisiaeobtaining 19.0 g L1 at 10 h of process of ethanol with a yield of ethanol and productivity of 0.50 g g1
and 1.90 g L1 h1
, respectively. Spent coffee grounds were considered a potential feedstock for biodiesel
and ethanol production.
2014