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The scarcity of essential minerals in the wort used for bioethanol production has long been a persistent concern in industrial processes. This scarcity can negatively impact various aspects of production, including yeast cell vitality and sugar-to-ethanol conversion. In this study, we assessed the nutritional profile of key components of the industrial bioethanol production process and identified nitrogen, phosphorus, magnesium, manganese, zinc, and copper ions deficiencies. Supplementation of fermentation assays with TMNitrofós was carried out until reaching the maximum allowed for manganese (24.5%), zinc (49.4%), and copper (8.8%). Laboratory-scale fermentation assays were conducted under varying conditions of soluble solids in the wort (20, 24, and 26°Brix). These experiments aimed to assess the primary productivity parameters in response to the application of TMNitrofós. Results showed that fermentations using wort with 24 and 26°Brix supplemented with TMNitrofós led to 7% higher fermentative efficiency compared to the control group. The supplemented fermentations demonstrated higher levels of cellular vitality (76.6%) compared to the control group (55.3%). Considering a scale-up in the bioethanol production process with TMNitrofós supplementation, an increase of 266 m3 of ethanol per month was achieved compared to the control group, resulting in cost savings of R$ 586,879.20. [ABSTRACT FROM AUTHOR]

The unwashed alkali-treated lignocellulose can be directly enzymatically hydrolyzed and fermented via pH adjustment with acids. The use of acids would give a burden on production cost. Furfural residue (FR) which is the acidic solid waste from lignocellulose-derived furfural production process was employed in this study as a pH regulator. The corn cob-derived FR was used to adjust the pH value of alkali-treated corn stover (PCS) to 4.8 for enzymatic hydrolysis and ethanol fermentation. The unwashed PCS adjusted by FR got higher enzymatic hydrolysis efficiency (EHE) than the washed PCS samples. Meanwhile, the mixing of PCS and FR had a synergistic effect on the EHE of PCS. The fermentation of enzymatic hydrolysate from unwashed PCS-FR mixture at 20% solid concentration could attain ethanol production of 26.54 ± 0.02 mg/mL with a yield of 89.53 ± 0.08%. This work created a novel recycling way of FR as a pH regulator for improving the bioconversion of alkali-treated lignocellulose. It also provided a novel clue for the valuable valorization of wastes from corn production. [ABSTRACT FROM AUTHOR]

Effective pretreatment is essential for successfully utilizing renewable resources such as lignocellulosic biomass in the production of bioethanol. In this study, ternary deep eutectic solvents (DESs), namely choline chloride/lactic acid/glycerol (ChCl/LA/Gly), choline chloride/oxalic acid/glycerol (ChCl/OA/Gly), choline chloride/lactic acid/ethylene glycol (ChCl/LA/EG), and choline chloride/oxalic acid/ethylene glycol (ChCl/OA/EG) were prepared and employed for the pretreatment of cellulose-rich Napier grass (NG). Post treatment, the NG hydrolysate was subjected to enzymatic saccharification followed by ethanol fermentation. The results showed effective delignification of NG after treatment with the prepared ternary DESs, with ChCl/LA/EG removing a maximum of 92.89% lignin. The efficiency of the prepared DESs is attributed to their low densities, pH, and viscosity. Enzymatic saccharification of ChCl/LA/EG-treated NG resulted in a 1.68 fold increase in reducing sugar yield compared to that of untreated NG. All pretreated NG produced more bioethanol via a separate hydrolysis and fermentation (SHF) process than untreated NG after Saccharomyces cerevisiae fermentation. A maximum of 0.37 g bioethanol/g of biomass was obtained from the one-pot process using ChCl/LA/Gly pretreatment. FTIR and XRD analyses of untreated and pretreated NG corroborated the efficacy of the ternary DESs on cellulose recovery and delignification. Also, enzymatic and microbial inhibition studies on the prepared DESs show their potential to be employed in a one-pot process for biorefinery. The results of the present investigation show the potential of utilizing eco-friendly DESs and renewable resources for the production of bioethanol, a viable option to fossil fuels. [ABSTRACT FROM AUTHOR]