Bioethanol production from sorghum grain with Zymomonas mobilis: increasing the yield and quality of raw distillates.

BACKGROUND: The present study aimed to demonstrate the superiority of bioethanol yield and its quality from sorghum using the granular starch degrading enzyme Stargen™ 002 over simultaneous saccharification and fermentation, and separate hydrolysis and fermentation using Zymomonas mobilis CCM 3881 and Ethanol Red® yeast. RESULTS: Bacteria were found to produce ethanol at higher yield than the yeast in all fermentations. The highest ethanol yield was obtained with Z. mobilis during 48 h of simultaneous saccharification and fermentation (83.85% theoretical yield) and fermentation with Stargen™ 002 (81.27% theoretical yield). Pre-liquefaction in fermentation with Stargen™ 002 did not improve ethanol yields for both Z. mobilis and Saccharomyces cerevisiae. Chromatographic analysis showed twice less total volatile compounds in distillates obtained after bacterial (3.29-5.54 g L-1 ) than after yeast (7.84-9.75 g L-1 ) fermentations. Distillates obtained after bacterial fermentation were characterized by high level of aldehydes (up to 65% of total volatiles) and distillates obtained after yeast fermentation of higher alcohols (up to 95% of total volatiles). The process of fermentation using granular starch hydrolyzing enzyme cocktail Stargen™ 002 resulted in low amounts of all volatile compounds in distillates obtained after bacterial fermentation, but the highest amounts in distillates obtained after yeast fermentation. CONCLUSION: The present study emphasizes the great potential of bioethanol production from sorghum with Z. mobilis using granular starch hydrolyzing enzyme Stargen™ 002, which leads to reduced water and energy consumption, especially when energy sources are strongly related to global climate change. © 2023 Society of Chemical Industry.

The comprehensive analysis of sorghum cultivated in Poland for energy purposes: Separate hydrolysis and fermentation and simultaneous saccharification and fermentation methods and their impact on bioethanol effectiveness and volatile by-products from the grain and the energy potential of sorghum straw.

The aim of this work was to study the potential of sorghum crop cultivated in European climate as an energy material. The investigation showed strong interaction between the fermentation method and the sorghum cultivar. It was also noted that the cultivar with the highest grain yield showed the highest yield of ethanol per hectare, achieving 1269 L/ha in SHF (separate hydrolysis and fermentation) and 1248 L/ha in SSF (simultaneous saccharification and fermentation). Chromatographic analysis of raw spirits showed that smaller amounts of impurities are formed in the SSF process than in the SHF process. The calorific value of sorghum straw was also measured, and amounted to 16,050-16,840 kJ/kg. The results have demonstrated the high value of sorghum as grain for bioethanol production and as straw as a valuable feedstock for forming pellets or briquettes.

Hematological Alterations as a Response to Exposure to Selected Fungicides in Common Carp (Cyprinus carpio L.).

The aim of the present study was to assess the hematological response of common carp to fungicides and to determine recovery patterns in fungicide-free water. Fish were exposed to mancozeb, prochloraz or tebuconazole (at concentrations of 1.0, 1.0 and 2.5 mg 1⁻¹, respectively) for 14 days followed by a 30-day recovery period. The following hematological parameters were examined after 1, 3 and 14 days of exposure as well as after recovery time: red blood cells (RBC), hematocrit (Het), total hemoglobin concentration (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), mean corpuscular hemoglobin (MCH), total number of leukocytes (WBC) and leukograms. All analyzed parameters revealed alterations in relation to control samples. The pattern of these changes was irregular, showing either an increase or decrease at different time points of the experiment and not all observed differences were statistically significant. The most noticeable fungicide-specific changes were,observed on the 1st and 14th days of chemical exposure. The majority of the parameters under investigation returned to the control levels after a detoxication period. However, some of the exerted effects were irreversible (Hb, MCH, MCHC and WBC for fish subjected to mancozeb; Hb, MCH, MCHC and monocyte count for fish subjected to prochloraz; Hct and monocyte number for fish subjected to tebuconazole). All of the observed hematoloaical changes were not toxin-soecific.

Reduction of water consumption in bioethanol production from triticale by recycling the stillage liquid phase.

BACKGROUND: The distillery stillage is a major and arduous byproduct generated during ethanol production in distilleries. The aim of this study was to evaluate the possibility of the stillage recirculation in the mashing process of triticale for non-byproducts production and reducing the fresh water consumption. The number of recirculation cycles which can be applied without disturbances in the ethanol fermentation process was investigated. MATERIAL AND METHODS: Winter triticale BOGO and "Ethanol Red" Saccharomyces cerevisiae yeast were used in the experiments. The method of non-pressure cooking was used for gelatinizingthe triticale, commercial α-amylase SPEZYME ETHYL and glucoamylase FERMENZYME L-400 were applied for starch liquefaction and saccharification. The process was conducted at 30°C for 72 h, next after distillation the stillage was centrifuged and the liquid fraction was used instead of 75% of process water. RESULTS: Ethanol yield from triticale fermentations during 40 cycles ranged between 82% and 95% of theoretical yield preserving yeast vitality and quantity on the same level. The obtained distillates were characterized with enhanced volatile compounds (fusel oil, esters, aldehydes, methanol) as well as protein and potassium concentrations. CONCLUSIONS: The liquid part of stillage was proved that can be reused instead of water in bioethanol production from triticale, without disturbing the fermentation process. This investigated solution of distillery byproducts utilization (liquid phase of stillage) constitutes the way which could significantly decrease the bioethanol production costs by reducing the water consumption, as well as wastewater production.

Use of Zymomonas mobilis and Saccharomyces cerevisiae mixed with Kluyveromyces fragilis for improved ethanol production from Jerusalem artichoke tubers.

Jerusalem artichoke mashed tubers were fermented using single yeasts and a bacterium as well as mixed culture of microorganisms. Kluyveromyces fragilis, a yeast with an active inulinase, was used together with either a commercial distillery yeast, Saccharomyces cerevisiae, or the bacterium Zymomonas mobilis. After batch fermentation the best ethanol concentration of 0.48 g g(-1) for the mixed population and 0.46 g g(-1) for the single population can be obtained. The theoretical yield of the mixed cultures was 2-12% higher than for the single microorganism.