Bioethanol Production from Cachaza as Hydrogen Feedstock: Effect of Ammonium Sulfate during Fermentation

Abstract

Abstract:Cachaza is a type of non-centrifugal sugarcane press-mud that, if it is not employed efficiently, generates water pollution, soil eutrophication, and the spread of possible pathogens. This biomass can be fermented to produce bioethanol. Our intention is to obtain bioethanol that can be catalytically reformed to produce hydrogen (H 2 ) for further use in fuel cells for electricity production. However, some impurities could negatively affect the catalyst performance during the bioethanol reforming process. Hence, the aim of this study was to assess the fermentation of Cachaza using ammonium sulfate ((NH 4 ) 2 SO 4 ) loadings and Saccharomyces cerevisiae strain to produce the highest ethanol concentration with the minimum amount of impurities in anticipation of facilitating further bioethanol purification and reforming for H 2 production. The results showed that ethanol production from Cachaza fermentation was about 50 g·L −1 and the (NH 4 ) 2 SO 4 addition did not affect its production. However, it significantly reduced the production of branched alcohols. When a 160 mg·L −1 (NH 4 ) 2 SO 4 was added to the fermentation culture, 2-methyl-1-propanol was reduced by 41% and 3-methyl-1-butanol was reduced by 6%, probably due to the repression of the catabolic nitrogen mechanism. Conversely, 1-propanol doubled its concentration likely due to the higher threonine synthesis promoted by the reducing sugar presence. Afterwards, we employed the modified Gompertz model to fit the ethanol, 2M1P, 3M1B, and 1-propanol production, which provided acceptable fits (R 2 > 0.881) for the tested compounds during Cachaza fermentation. To the best of our knowledge, there are no reports of the modelling of aliphatic production during fermentation; this model will be employed to calculate yields with further scaling and for life cycle assessment.

Feasibility Assessment of a Bioethanol Plant in the Northern Netherlands

“…In 2017, 2718 t of oil equivalents (toe) of bioethanol was consumed for transport in Europe, of which 121 toe was consumed by the Netherlands [33]. Although much research has been done on the ethanol production from lignocellulosic biomass [34][35][36][37][38][39][40][41][42][43][44], the economic viability of a bioethanol plant in the Northern Netherlands is yet unknown. Therefore, this research aims to investigate the feasibility of a bioethanol plant treating organic residues (sugar beet pulp and grass straw) in the Northern Netherlands.…”

Environmental and economic analysis of bioethanol production from sugarcane molasses and agave juice

“…Afterward, came clarification at which point the juice was purified, with all impurities removed in the form of insoluble calcium salts (Consorcio 2012 ). Sucrose was then recovered from these solid impurities by filtration, to obtain juice and a solid by-product (sugarcane press mud) which can be used as compost (Consorcio 2012 ; Sanchez et al 2017 ).…”

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

“…Samples were fermented in 15 mL centrifuge tubes with a total volume of 4 mL and an inoculum size of 10 vol.%. Inoculum was prepared according to previous studies [14]. Dry Saccharomyces cerevisiae (Ethanol Red ® , Fermentis by Lesaffre, Marcq-en-Baroeul, France) was activated in water at 30 • C for 20 min.…”

“…Their formation is influenced by different variables such as nitrogen, temperature, pH, dissolved oxygen, and yeast strain [12,13]. For instance, we reported that the addition of ammonium sulfate ((NH 4 ) 2 SO 4 ) decreased the amount of fusel alcohol, mainly 2-methyl-1-propanol, during the fermentation of sugarcane press-mud at 30 • C [14]. Arshad et al [15] assessed the effect of several fermentation variables, such as substrate concentration, pH, and inoculum size, over the fusel alcohol concentration during fermentation of sugarcane molasses at 30 • C. They concluded that all the assessed variables have a significant effect (p < 0.05) over the formation of fusel alcohols.…”

“…Those strains are supplied by Fermentis, and all can be used for very high gravity fermentation. Strain HG-1, hereafter named as Ethanol Red, has been employed for producing bioethanol from sugarcane press-mud [10,14,24]. In addition, it has been used for producing beverage spirits like vodka, where the optimum operating temperature ranges between 25 and 33 • C. Strain C-70 is employed due to its high attenuation and ethanol tolerance.…”