Bioethanol Production from Sugarcane Press-Mud: Assessment of the Fermentation Conditions to Reduce Fusel Alcohol

Abstract

Within a biorefinery context, bioethanol is a promising platform molecule since it can be used as raw material to produce a wide spectrum of valuable industrial products such as H2 and light olefins. However, the presence of impurities limits the conversion of bioethanol in these products. Herein, we aimed to determine the proper pretreatment and fermentation conditions to yield bioethanol with a low content of impurities, such as 3-methyl-1-butanol, by using sugarcane press-mud as feedstock. To do so, a BoxBehnken methodology was employed to select proper pretreatment and fermentation conditions. Factors assessed were temperature, stirring, and pH during fermentation of hydrolysates coming from two different pretreatment methods named as hydrothermal and acid hydrolysis. Results showed that the fermentation temperature should be kept between 26–30 °C to assure at least 91 g/L ethanol. The fusel alcohol content would be reduced by 22% at 30 °C, pH = 4.5, and 200 rpm if sugarcane press-mud is pretreated under acid hydrolysis conditions (T = 130 °C, t = 1 h, 16 g HNO3/kg solid). Further studies should aim to integrate these conditions within a biorefinery concept to yield valuable products such as H2 and ethylene.

Biomass Potential for Producing Power via Green Hydrogen

“…The composition of H 2 was exported to Matlab to calculate the fuel cell power according to Section 2.2. The efficiency of the process was calculated according to Equation (12), where P NET is the net power produced in the HT-PEMFC, m EtOH is the mass flow of ethanol (kg s −1 ), and Q Total is the total thermal energy required in the process.…”

“…Selection of the purification technology depends on the features of the raw bioethanol, which is produced from a wide spectrum of biomass such as corn grain, sugar beet, sugarcane juice, molasses, sugarcane press-mud, wheat straw, wood hydrolysates, cassava, and more [4,11,12]. Fermentation of those biomass results in a raw bioethanol with different ethanol profiles that, consequently, will influence H 2 production by ESR and, subsequently, the power production in a HT-PEMFC [4].…”