Ethanol Production from Hydrothermally-Treated Biomass from West Africa

Abstract

Despite the abundance of diverse biomass resources in Africa, they have received little research and development focus. This study presents compositional analysis, sugar, and ethanol yields of hydrothermal pretreated (195 °C, 10 min) biomass from West Africa, including bamboo wood, rubber wood, elephant grass, Siam weed, and coconut husk, benchmarked against those of wheat straw. The elephant grass exhibited the highest glucose and ethanol yields at 57.8% and 65.1% of the theoretical maximums, respectively. The results show that the glucose yield of pretreated elephant grass was 3.5 times that of the untreated material, while the ethanol yield was nearly 2 times higher. Moreover, the sugar released by the elephant grass (30.8 g/100 g TS) was only slightly lower than by the wheat straw (33.1 g/100 g TS), while the ethanol yield (16.1 g/100 g TS) was higher than that of the straw (15.26 g/100 g TS). All other local biomass types studied exhibited sugar and ethanol yields below 33% and 35% of the theoretical maximum, respectively. Thus, elephant grass is a highly promising biomass source for ethanol production in Africa.

Combining Autoclaving with Mild Alkaline Solution as a Pretreatment Technique to Enhance Glucose Recovery from the Invasive Weed Chloris barbata

“…The total lignin fraction, that is AIL (14.78%) and ASL (4.89%), formed about 20% of the total raw biomass, while other minor components, such as ash and ethanol extractives, accounted for nearly 8% and 7%, respectively. The glucan content of C. barbata in this study is in agreement with that of other previously studied invasive weed species, such as; Chromolaena odorata (36.2%), Pennisetum purpureum (32.0%) [29], A. aspera (45.9%), and S. acuta (46.9%) [7]. However, the lignin content is an indication for an effective pretreatment process to enhance accessibility to cellulose by cellulase enzymes [30].…”

Evaluation of different pretreatments of Napier grass for enzymatic saccharification and ethanol production

“…In other two methods, the use of dilute sulfuric acid at high temperature caused cellulose hydrolysis to glucose and also glucose degradation to HMF, resulting in lower glucose recovery yields from raw material. The glucose yield is also higher than that from elephant grass biomass after hydrothermal pretreatment (57.8%) and much higher than that from milled biomass without pretreatment (24.8%) . The removal of hemicellulose could also play a dominate role for enzyme accessibility and efficiency of enzymatic saccharification as suggested by Leu and Zhu .…”

“…The glucose yield is also higher than that from elephant grass biomass after hydrothermal pretreatment (57.8%) and much higher than that from milled biomass without pretreatment (24.8%). 23 The removal of hemicellulose could also play a dominate role for enzyme accessibility and efficiency of enzymatic saccharification as suggested by Leu and Zhu. 24 As shown in the present work, even the single use of alkaline pretreatment could result in the removal of 67.1% hemicellulose, leading to efficient lignocellulose saccharification.…”

Alkali and glycerol pretreatment of West African biomass for production of sugars and ethanol

“…In this study, KOH and glycerol pretreatments are applied to four West African biomasselephant grass, Siam weed, rubber wood and bamboo woodand their effects on biomass conversion to sugars and ethanol are discussed. The results are benchmarked against a previous study based on hydrothermal pretreatment (Bensah et al, 2015b) at 195 o C, 10 min at 6% solids loading using a loop reactor.…”