Bio-ethanol production from wet coffee processing waste in Ethiopia

Abstract

Large amounts of coffee residues are generated from coffee processing plants in Ethiopia. These residues are toxic and possess serious environmental problems following the direct discharge into the nearby water bodies which cause serious environmental and health problems. This study was aimed to quantify wet coffee processing waste and estimate its bio-ethanol production. The study showed that the wastes are potential environmental problems and cause water pollution due to high organic component and acidic nature. The waste was hydrolyzed by dilute H2SO4 (0.2, 0.4, 0.6, 0.8 and 1 M) and distilled water. Total sugar content of the sample was determined titrimetrically and refractometry. Maximum value (90%) was obtained from hydrolysis by 0.4 M H2SO4. Ethanol production was monitored by gas chromatography. The optimum yield of ethanol (78%) was obtained from the sample hydrolyzed by 0.4 M H2SO4 for 1 h at hydrolysis temperature of 100 °C and after fermentation for 24 h and initial pH of 4.5. Based on the data, it was concluded that reuse of the main coffee industry wastes is of significant importance from environmental and economical view points. In conclusion, this study has proposed to utilize the wet coffee processing waste to produce bio-ethanol which provides the alternative energy source from waste biomass and solves the environmental waste disposal as well as human health problem.

Torrefaction of Coffee Husk Flour for the Development of Injection-Molded Green Composite Pieces of Polylactide with High Sustainability

“…The CSS, which is the main by-product of the roasting process, includes dietary fiber (50-60 wt%) protein (16-19 wt%), fat (1.56-3.28 wt%), and ash (7 wt%) [24]. The main current value-adding applications include biofuel [25] or energy purposes [26], fertilizer production [27], dietary fiber [28], and bioactive compound extraction [29]. However, animal feeding is limited by the presence of caffeine and tannins, phenolic compounds that show anti-nutritional properties [30].…”

Fabrication and Properties of Hybrid Coffee-Cellulose Aerogels from Spent Coffee Grounds

“…The presence of natural toxic organic compounds such as caffeine, tannins and polyphenols in SCG make it a pollution hazard when disposed of in the environment [3][4][5]. In addition, the high organic content in SCG requires a huge amount of oxygen to biodegrade it, thus making undesirable its reckless disposal into water [6,7]. Nowadays, the most common way to discard SCG is through landfills.…”

Secado de Pulpa de Café: Condiciones de Proceso, Modelación Matemática y Efecto sobre Propiedades Fisicoquímicas

“…Actualmente para uso de estos residuos se elabora ensilaje para la alimentación animal, torta de pulpa de café, jugo tratado con microorganismos para el consumo animal (Noriega et al, 2009), adicionalmente han sido utilizados para cultivo de hongos (Murthy y Manonmani, 2008), producción de enzimas (Buntić et al, 2016;Ngo y Phan, 2016;Torres-Mancera et al, 2011), biocombustibles (Gouvea et al, 2009;Woldesenbet, Woldeyes, y Chandravanshi, 2016) y compostaje (Hachicha et al, 2012). Teniendo en cuenta que la pulpa de café es altamente perecedera debido a su alto contenido de humedad, se generan pérdidas por deterioro químico y microbiano (Ruiz-López et al, 2011).…”