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AbstractGlobal energy demand is experiencing a notable surge due to growing energy security. Renewable energy sources, like ethanol, are becoming more viable. In the present study, the application of a PSO-PID (Particle Swarm Optimization – Proportional Integral Derivative) controller with a split-range control strategy was suggested for the regulation of temperature within the fermentation system. To optimize performance, a POS-PID controller with a split-range arrangement utilizing two control valves for hot and cold utilities was constructed. The study began by examining the open-loop dynamic response of the system to inlet temperature and concentration disturbances during ethanol production fermentation. Subsequently, a transfer function model was developed through linearization at the steady-state operating point. The split-range controller structure, implemented by optimizing the PSO-PID controller parameters using PSO, effectively demonstrated temperature control in simulations of a nonlinear model. In this investigation, the ethanol fermentation system was modeled as a CSTR using a modified Monod equation for microbial growth kinetics. Various dynamic behavioral disturbances were explored and verified in the model with plant data in this study. The simulation model results were validated through plant data. The proposed method showed superior closed-loop performance with respect to errors, with the actuators proving to be effective than other reported methods for temperature control. [ABSTRACT FROM AUTHOR]

Thermophilic actinomycetes are commonly found in extreme environments and can thrive and adapt to extreme conditions. These organisms exhibit substantial variation and garnered significant interest due to their remarkable enzymatic activities. This study evaluated the potential of Streptomyces griseorubens NBR14 and Nocardiopsis synnemataformans NBRM9 strains to produce thermo-stable amylase via submerged fermentation using wheat and bean straw. The Box-Behnken design was utilized to determine the optimum parameters for amylase biosynthesis. Subsequently, amylase underwent partial purification and characterization. Furthermore, the obtained hydrolysate was applied for ethanol fermentation using Saccharomyces cerevisiae. The optimal parameters for obtaining the highest amylase activity by NBR14 (7.72 U/mL) and NBRM9 (26.54 U/mL) strains were found to be 40 and 30 °C, pH values of 7, incubation time of 7 days, and substrate concentration (3 and 2 g/100 mL), respectively. The NBR14 and NBRM9 amylase were partially purified, resulting in specific activities of 251.15 and 144.84 U/mg, as well as purification factors of 3.91 and 2.69-fold, respectively. After partial purification, the amylase extracted from NBR14 and NBRM9 showed the highest activity level at pH values of 9 and 7 and temperatures of 50 and 60 °C, respectively. The findings also indicated that the maximum velocity (Vmax) for NBR14 and NBRM9 amylase were 57.80 and 59.88 U/mL, respectively, with Km constants of 1.39 and 1.479 mM. After 48 h, bioethanol was produced at concentrations of 5.95 mg/mL and 9.29 mg/mL from hydrolyzed wheat and bean straw, respectively, through fermentation with S. cerevisiae. Thermophilic actinomycetes and their α-amylase yield demonstrated promising potential for sustainable bio-ethanol production from agro-byproducts. [ABSTRACT FROM AUTHOR]

The study aims to enhance ethanol production by Wickerhamomyces subpelliculosus ZE75 isolated from marine sediment. In addition, analyzing the kinetic parameters of ethanol production and optimization of the fermentation conditions was performed. The marine yeast isolate ZE75 was selected as the front runner ethanol-producer, with an ethanol yield of 89.77 gL−1. ZE75 was identified relying on the phenotypic and genotypic characteristics of W. subpelliculosus. The genotypic characterization based on the Internal Transcribed Spacer (ITS) sequence was deposited in the GenBank database with the accession number OP715873. The maximum specific ethanol production rate (vmax) was 0.482 gg−1 h−1 at 175 gL−1 glucose concentration, with a high accuracy of R2 0.95. The maximum growth specific rates (μmax) were 0.141 h−1 obtained at 150 gL−1 glucose concentration with R2 0.91. Optimization of the fermentation parameters such as pH and salinity has been achieved. The highest ethanol yield 0.5637 gg−1 was achieved in a 100% natural seawater-based medium. The maximum ethanol production of 104.04 gL−1 was achieved at pH 4.5 with a specific ethanol rate of 0.1669 gg−1 h−1. The findings of the present study recommend the possibility of ethanol production from a seawater-based medium on a large scale using W. subpelliculosus ZE75. [ABSTRACT FROM AUTHOR]

Background: Production of cheese whey in the EU exceeded 55 million tons in 2022, resulting in lactose-rich effluents that pose significant environmental challenges. To address this issue, the present study investigated cheese-whey treatment via membrane filtration and the utilization of its components as fermentation feedstock. A simulation model was developed for an industrial-scale facility located in Italy's Apulia region, designed to process 539 m3/day of untreated cheese-whey. The model integrated experimental data from ethanolic fermentation using a selected strain of Kluyveromyces marxianus in lactose-supplemented media, along with relevant published data. Results: The simulation was divided into three different sections. The first section focused on cheese-whey pretreatment through membrane filtration, enabling the recovery of 56%w/w whey protein concentrate, process water recirculation, and lactose concentration. In the second section, the recovered lactose was directed towards fermentation and downstream anhydrous ethanol production. The third section encompassed anaerobic digestion of organic residue, sludge handling, and combined heat and power production. Moreover, three different scenarios were produced based on ethanol yield on lactose (YE/L), biomass yield on lactose, and final lactose concentration in the medium. A techno-economic assessment based on the collected data was performed as well as a sensitivity analysis focused on economic parameters, encompassing considerations on cheese-whey by assessing its economical impact as a credit for the simulated facility, dictated by a gate fee, or as a cost by considering it a raw material. The techno-economic analysis revealed different minimum ethanol selling prices across the three scenarios. The best performance was obtained in the scenario presenting a YE/L = 0.45 g/g, with a minimum selling price of 1.43 €/kg. Finally, sensitivity analysis highlighted the model's dependence on the price or credit associated with cheese-whey handling. Conclusions: This work highlighted the importance of policy implementation in this kind of study, demonstrating how a gate fee approach applied to cheese-whey procurement positively impacted the final minimum selling price for ethanol across all scenarios. Additionally, considerations should be made about the implementation of the simulated process as a plug-in addition in to existing processes dealing with dairy products or handling multiple biomasses to produce ethanol. [ABSTRACT FROM AUTHOR]

In this article, the problem of real‐time estimation of the fermentative ethanol process is tackled. The considered observer is a model‐based technique that is robust regarding the model parameter uncertainties and inline noisy measurements. An unstructured kinetic model was used to describe the production of ethanol in a batch bioreactor for Saccharomyces cerevisiae. The biomass concentration was selected as the measured bioreactor´s output via an inline device, where the estimate variables were the substrate and ethanol concentrations. An experimental prototype was constructed to demonstrate the observer's real‐time performance. The experimental results show that the robust, smooth sliding mode observer performs better than the standard proportional sliding mode observer. [ABSTRACT FROM AUTHOR]

[Display omitted] • Raman spectroscopy and chemometrics track metabolic changes in individual yeast cells. • Yeast cells exhibit 3 stages during high gravity ethanol fermentation. • Unique protein structure and increased triacylglycerol synthesis as a defense from ethanol stress. Saccharomyces cerevisiae is the most common microbe used for the industrial production of bioethanol, and it encounters various stresses that inhibit cell growth and metabolism during fermentation. However, little is currently known about the physiological changes that occur in individual yeast cells during ethanol fermentation. Therefore, in this work, Raman spectroscopy and chemometric techniques were employed to monitor the metabolic changes of individual yeast cells at distinct stages during high gravity ethanol fermentation. Raman tweezers was used to acquire the Raman spectra of individual yeast cells. Multivariate curve resolution-alternating least squares (MCR-ALS) and principal component analysis were employed to analyze the Raman spectra dataset. MCR-ALS extracted the spectra of proteins, phospholipids, and triacylglycerols and their relative contents in individual cells. Changes in intracellular biomolecules showed that yeast cells undergo three distinct physiological stages during fermentation. In addition, heterogeneity among yeast cells significantly increased in the late fermentation period, and different yeast cells may respond to ethanol stress via different mechanisms. Our findings suggest that the combination of Raman tweezers and chemometrics approaches allows for characterizing the dynamics of molecular components within individual cells. This approach can serve as a valuable tool in investigating the resistance mechanism and metabolic heterogeneity of yeast cells during ethanol fermentation. [ABSTRACT FROM AUTHOR]

• SCF as a kind of periodic operation is analyzed for its superiority over the steady-state counterpart. • SCF as a kind of impulsive control is evaluated for possible repetition property in long-term operation. • Optimal on-off operation strategies are formulated with guaranteed periodic stability and superiority. Fuel ethanol is highlighted for being renewable and carbon neutral, but a multi-scale challenge exists that hampers its role as a future energy substitute, and with the breakthrough of cellulose pretreatment and enzyme hydrolysis technology, fermentation itself has become one of the main limiting factors for process enhancement. To tackle the problem, this paper studies periodic operation strategies to improve process performance and avoid possible instabilities. Firstly, superiority by periodic operation over the corresponding steady-state operation is verified. Then, to settle the problem of possible instabilities under impulsive control, stability of state-impulsive control is conducted and for the studied case, any self-cycling fermentation starts from batch mode with 50 % discharge-and-refill portion exhibits superior repeatability property, which allows continuous fermentation to operate under very slow overall dilution rate to cope with the extreme slow fermentation rate. Finally, on-off operation problem is formulated that is governed by a multidimensional nonlinear system, affine to the manipulated variable that is under the isoperimetric constraint; with the use of Pontryagin maximum principle, the optimal synthesis of the optimal strategies under integral constraint is computed out, and a practically plausible on-off operation strategy for ethanol fermentation is formulated with guaranteed periodic stability and optimality. [ABSTRACT FROM AUTHOR]

Despite the significant progress in the research, the problem of finding an efficient method for producing bioethanol from renewable lignocellulosic waste materials remains unresolved. Our investigation aimed to assess the efficacy of ethanol production from sugar beet pulp (SBP) utilising various approaches, including pretreatment variations, enzymatic processes, and microbial hydrolysis. Our research involved using the post-cultivation concentrate of T. viride LOCK 0588 grown in the SBP-based medium as a source of enzymes. The SBP hydrolysis process was carried out for 48 h at 50 °C. The quantity of sugar released, up to 61 g dm−3, through the utilisation of this extract proved to be on par with the outcomes achieved by the application of the commercial Cellic Ctec2 preparation. The final yields of the ethanol production with the use of the coculture of S. cerevisiae (Ethanol Red) and Scheffersomyces stipitis LOCK 0047 strain were in the range 5.1 ± 0.11 kg 100 kg−1 ÷ 5.38 ± 0.11 kg 100 kg−1. These results provide a solid basis for improving larger-scale industrial procedures that involve converting SBP into bioethanol using a cost-efficient approach of microbial hydrolysis with T. viride and a blend of pentose and hexose fermenting yeast. [ABSTRACT FROM AUTHOR]

A high‐quality filler within mixed matrix membranes, coupled with uniform dispersity, endows a high‐efficiency transfer pathway for the significant improvement on separation performance. In this work, a zeolite‐typed MCM‐22 filler is reported that is doped into polydimethylsiloxane (PDMS) matrix by ultrafast photo‐curing technique. The unique structure of nanosheets assembly layer by layer endows the continuous transfer channels towards penetrate molecules because of the inter‐connective nanosheets within PDMS matrix. Furthermore, an ultrafast freezing effect produced by fast photo‐curing is used to overcome the key issue, namely filler aggregation, and further eliminates defects. When pervaporative separating a 5 wt% ethanol aqueous solution, the resulting MCM‐22/PDMS membrane exhibits an excellent membrane flux of 1486 g m−2 h−1 with an ethanol separation factor of 10.2. Considering a biobased route for ethanol production, the gas stripping and vapor permeation through this membrane also shows a great enrichment performance, and the concentrated ethanol is up to 65.6 wt%. Overall, this MCM‐22/PDMS membrane shows a high separation ability for ethanol benefited from a unique structure deign of fillers and ultrafast curing speed of PDMS, and has a great potential for bioethanol separation from cellulosic ethanol fermentation. [ABSTRACT FROM AUTHOR]

Background: Saccharomyces cerevisiae is an important microorganism in ethanol synthesis, and with sugarcane molasses as the feedstock, ethanol is being synthesized sustainably to meet growing demands. However, high-concentration ethanol fermentation based on high-concentration sugarcane molasses—which is needed for reduced energy consumption of ethanol distillation at industrial scale—is yet to be achieved. Results: In the present study, to identify the main limiting factors of this process, adaptive laboratory evolution and high-throughput screening (Py-Fe3+) based on ARTP (atmospheric and room-temperature plasma) mutagenesis were applied. We identified high osmotic pressure, high temperature, high alcohol levels, and high concentrations of K+, Ca2+, K+ and Ca2+ (K+&Ca2+), and sugarcane molasses as the main limiting factors. The robust S. cerevisiae strains of NGT-F1, NGW-F1, NGC-F1, NGK+, NGCa2+ NGK+&Ca2+-F1, and NGTM-F1 exhibited high tolerance to the respective limiting factor and exhibited increased yield. Subsequently, ethanol synthesis, cell morphology, comparative genomics, and gene ontology (GO) enrichment analysis were performed in a molasses broth containing 250 g/L total fermentable sugars (TFS). Additionally, S. cerevisiae NGTM-F1 was used with 250 g/L (TFS) sugarcane molasses to synthesize ethanol in a 5-L fermenter, giving a yield of 111.65 g/L, the conversion of sugar to alcohol reached 95.53%. It is the highest level of physical mutagenesis yield at present. Conclusion: Our results showed that K+ and Ca2+ ions primarily limited the efficient production of ethanol. Then, subsequent comparative transcriptomic GO and pathway analyses showed that the co-presence of K+ and Ca2+ exerted the most prominent limitation on efficient ethanol production. The results of this study might prove useful by promoting the development and utilization of green fuel bio-manufactured from molasses. [ABSTRACT FROM AUTHOR]

Summary: This study focuses primarily on the real‐time monitoring of reducing sugar levels throughout solid‐state ethanol fermentation. A predictive model for accurate quantification of reducing sugar levels will be formulated through a comprehensive analysis of near‐infrared spectra across different fermentation stages. Building a predictive model using Adaptive Boosting (AdaBoost), The spectral data was pre‐processed using the Standard Normal Variate (SNV) method, followed by feature band selection using the Genetic Algorithm (GA), resulting in the identification of 181 characteristic wavelengths. The resulting GA‐AdaBoost model has excellent performance metrics: Rc2 of 0.989, RMSEC of 0.393, Rp2 of 0.978, RMSEP of 0.640, RPD of 6.651 and RER of 0.142. Comparative evaluations against Competitive Adaptive Reweighted Sampling (CARS), Successive Projection Algorithm (SPA), Uninformative Variable Elimination (UVE) and Principal Component Analysis (PCA) consistently underscore the superior efficacy of the GA‐AdaBoost model. These results robustly confirm its reliability in accurately quantifying reducing sugars in solid‐state fermentation processes. [ABSTRACT FROM AUTHOR]

Saccharomyces cerevisiae is a widely used strain for ethanol fermentation; meanwhile, efficient utilization of glucose could effectively promote ethanol production. The PFK1 gene is a key gene for intracellular glucose metabolism in S. cerevisiae. Our previous work suggested that although deletion of the PFK1 gene could confer higher oxidative tolerance to S. cerevisiae cells, the PFK1Δ strain was prone to contamination by other microorganisms. High interspecies microbial competition ability is vital for the growth and survival of microorganisms in co-cultures. The result of our previous studies hinted us a reasonable logic that the EMP (i.e., the Embden-Meyerhof-Parnas pathway, the glycolytic pathway) key gene PFK1 could be involved in regulating interspecies competitiveness of S. cerevisiae through the regulation of glucose utilization and ethanol production efficiency. The results suggest that under 2% and 5% glucose, the PFK1Δ strain showed slower growth than the S288c wild-type and TDH1Δ strains in the lag and exponential growth stages, but realized higher growth in the stationary stage. However, relative high supplement of glucose (10%) eliminated this phenomenon, suggesting the importance of glucose in the regulation of PFK1 in yeast cell growth. Furthermore, during the lag growth phase, the PFK1Δ strain displayed a decelerated glucose consumption rate (P < 0.05). The expression levels of the HXT2, HXT5, and HXT6 genes decreased by approximately 0.5-fold (P < 0.05) and the expression level of the ZWF1 exhibited a onefold increase in the PFK1Δ strain compared to that in the S. cerevisiae S288c wild-type strain (P < 0.05).These findings suggested that the PFK1 inhibited the uptake and utilization of intracellular glucose by yeast cells, resulting in a higher amount of residual glucose in the medium for the PFK1Δ strain to utilize for growth during the reverse overshoot stage in the stationary phase. The results presented here also indicated the potential of ethanol as a defensive weapon against S. cerevisiae. The lower ethanol yield in the early stage of the PFK1Δ strain (P < 0.001) and the decreased expression levels of the PDC5 and PDC6 (P < 0.05), which led to slower growth, resulted in the strain being less competitive than the wild-type strain when co-cultured with Escherichia coli. The lower interspecies competitiveness of the PFK1Δ strain further promoted the growth of co-cultured E. coli, which in turn activated the ethanol production efficiency of the PFK1Δ strain to antagonize it from E. coli at the stationary stage. The results presented clarified the regulation of the PFK1 gene on the growth and interspecies microbial competition behavior of S. cerevisiae and would help us to understand the microbial interactions between S. cerevisiae and other microorganisms. Key points: • PFK1Δ strain could realize reverse growth overshoot at the stationary stage • PFK1 deletion decreased ethanol yield and interspecific competitiveness • Proportion of E. coli in co-culture affected ethanol yield capacity of yeast cells [ABSTRACT FROM AUTHOR]

The co-cultivation of sake yeast (AK25, K901, K1401, or K1801 strain) and the kuratsuki Bacillus A-10 and/or Priestia B-12 strains in koji solution was performed to demonstrate the effects of these two kuratsuki bacteria on sake taste. The results showed that the Brix and acidity patterns of sake preparations produced with and without these kuratsuki bacteria were very similar. This indicated that the addition of these kuratsuki bacteria did not inhibit ethanol fermentation or organic acid production by sake yeast. A taste recognition device showed that the effects of these kuratsuki bacteria on the saltiness and sourness of sake were greater than those on other taste properties. Astringency stimulation and saltiness of sake produced using the sake yeast K901 were increased by Bacillus A-10 and decreased by Priestia B-12. Except for these two cases, the taste intensities of sake preparations produced with the Bacillus A-10 and Priestia B-12 strains were very similar, but differed from those of sake produced with kuratsuki Kocuria. These results support our hypothesis that the flavor and taste of sake can be controlled by utilizing the interactions between kuratsuki bacteria and sake yeast. For crating the desired sake taste, a combination of kuratsuki bacteria and sake yeast should be considered. [ABSTRACT FROM AUTHOR]

To improve ethanol production, carbon and microbial sources were derived from corncob and molasses. Before investigating simultaneous saccharification and fermentation (SSF), the boiled corncob was vacuum-ensiled and the molasses was diluted. The optimal ensiling time of 4 days increased not only the amount of fermentable sugar but also the population of beneficial microorganisms. The proper dilution of molasses at a ratio of 1:3 molasses to boiled water reduced both the contamination problem and the inhibition of ethanol fermentation. The combination of the ensiled corncob and the diluted molasses could provide a substrate that is suitable for SSF without the addition of enzymes, supplements, or yeast strains. The substrate contained the optimal concentration of initial sugar (174.631 ± 0.975 g/L) and viable microorganisms (1.9×106 ± 0.1×106 CFU/mL of total bacteria and 1.0x105 ± 0.1×105CFU/mL of yeast) that could continue to hydrolyze and ferment carbohydrates in the substrate for the SSF. Using a ratio of 1:3 of ensiled corncob to diluted molasses, a pH of 4.5, and a temperature of 27 °C for 72 h, the SSF produced the highest concentration of ethanol at 93.345 ± 0.062 g/L. This work provides a cost-effective process that requires no enzyme or yeast, is simply technology, and is friendly to the environment, while the remaining solid fraction can be utilized as a suitable feedstock for biogas production. [ABSTRACT FROM AUTHOR]

Saccharomyces cerevisiae is a widely used strain for ethanol fermentation; meanwhile, efficient utilization of glucose could effectively promote ethanol production. The PFK1 gene is a key gene for intracellular glucose metabolism in S. cerevisiae. Our previous work suggested that although deletion of the PFK1 gene could confer higher oxidative tolerance to S. cerevisiae cells, the PFK1Δ strain was prone to contamination by other microorganisms. High interspecies microbial competition ability is vital for the growth and survival of microorganisms in co-cultures. The result of our previous studies hinted us a reasonable logic that the EMP (i.e., the Embden-Meyerhof-Parnas pathway, the glycolytic pathway) key gene PFK1 could be involved in regulating interspecies competitiveness of S. cerevisiae through the regulation of glucose utilization and ethanol production efficiency. The results suggest that under 2% and 5% glucose, the PFK1Δ strain showed slower growth than the S288c wild-type and TDH1Δ strains in the lag and exponential growth stages, but realized higher growth in the stationary stage. However, relative high supplement of glucose (10%) eliminated this phenomenon, suggesting the importance of glucose in the regulation of PFK1 in yeast cell growth. Furthermore, during the lag growth phase, the PFK1Δ strain displayed a decelerated glucose consumption rate (P < 0.05). The expression levels of the HXT2, HXT5, and HXT6 genes decreased by approximately 0.5-fold (P < 0.05) and the expression level of the ZWF1 exhibited a onefold increase in the PFK1Δ strain compared to that in the S. cerevisiae S288c wild-type strain (P < 0.05).These findings suggested that the PFK1 inhibited the uptake and utilization of intracellular glucose by yeast cells, resulting in a higher amount of residual glucose in the medium for the PFK1Δ strain to utilize for growth during the reverse overshoot stage in the stationary phase. The results presented here also indicated the potential of ethanol as a defensive weapon against S. cerevisiae. The lower ethanol yield in the early stage of the PFK1Δ strain (P < 0.001) and the decreased expression levels of the PDC5 and PDC6 (P < 0.05), which led to slower growth, resulted in the strain being less competitive than the wild-type strain when co-cultured with Escherichia coli. The lower interspecies competitiveness of the PFK1Δ strain further promoted the growth of co-cultured E. coli, which in turn activated the ethanol production efficiency of the PFK1Δ strain to antagonize it from E. coli at the stationary stage. The results presented clarified the regulation of the PFK1 gene on the growth and interspecies microbial competition behavior of S. cerevisiae and would help us to understand the microbial interactions between S. cerevisiae and other microorganisms. Key points: • PFK1Δ strain could realize reverse growth overshoot at the stationary stage • PFK1 deletion decreased ethanol yield and interspecific competitiveness • Proportion of E. coli in co-culture affected ethanol yield capacity of yeast cells [ABSTRACT FROM AUTHOR]

In this study, sorghum meal underwent 2–10 kGy electron beam irradiation (EBI) to investigate alterations in its elemental composition, relevant physicochemical characteristics, and enzymatic hydrolysis fermentation properties. The results indicated a decrease in amylose content and an increase in reducing sugar content in sorghum meal after EBI, along with severe damage to the internal structure of starch granules, leading to increased solubility in water. Furthermore, irradiation enhanced the shear resistance and gelatinization stability of sorghum meal paste. Most importantly, EBI-induced degradation of sorghum starch molecules enhanced their susceptibility to interact with α-amylase, significantly improving the enzymatic hydrolysis and alcohol fermentation efficiency of sorghum meal. At an irradiation dose of 8 kGy, raw and cooked sorghum meal exhibited a 43.40% and 33.33% increase in ethanol concentration and a 43.44% and 30.29% increase in ethanol yield, respectively. This finding indicated that irradiation is an effective pretreatment method for starch-based ethanol fermentation. [Display omitted] • Using EBI as a pretreatment for sorghum meal ethanol fermentation. • Sorghum starch molecules degraded after EBI treatment. • EBI notably enhanced sorghum meal's enzymatic saccharification efficiency. • The ethanol concentration and yield peaked at an EBI dose of 8 kGy. • EBI coupled with high-temperature cooking notably improved fermentation efficiency. [ABSTRACT FROM AUTHOR]

• Both membership function classification method and principal component analysis comprehensive evaluation method can be used to evaluate the waterlogging tolerance of pumpkin resources. • Of the 27 pumpkin germplasm, 20 were evaluated as MWT, 4 as WT, and 1 each as HWT, WS, and HWS. • The water-resistant pumpkin can maintain the balance of reactive oxygen synthesis and removal, the membrane peroxidation degree is low, and more chlorophyll can be synthesized to resist stress. This study used 27 Chinese pumpkin resources for the waterlogging treatment and analyzed 16 growth and physiological indicators, including plant height and stem diameter. The waterlogging-tolerant and waterlogging-sensitive pumpkin resources were selected using the membership function grading method and principal component analysis. The changes in the biochemical indicators of pumpkins under waterlogging stress were also studied. The results showed that among the 27 pumpkin resources, five were waterlogging-tolerant materials ('013-2′, 'Changyi', 'Universal female parent', '450′, and 'Changer'), two were waterlogging-sensitive materials ('063-2′ and '367-2′), and the remaining were moderately tolerant to waterlogging. Waterlogging stress increased the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) and the contents of proline and pyruvate in pumpkins, which were higher in waterlogging-tolerant pumpkins than in waterlogging-sensitive ones. The malondialdehyde content of the waterlogging-tolerant pumpkins was lower than that of the waterlogging-sensitive ones. The alcohol dehydrogenase (ADH) and pyruvate dehydrogenase complex (PDC) activities in the root of waterlogging-tolerant pumpkins showed an upward trend, while the lactate dehydrogenase (LDH) activity showed an initial downward trend and then upward trend. The ADH, PDC, and LDH enzyme activities of the waterlogging-sensitive pumpkins increased initially and then decreased. The contents of chlorophyll a, chlorophyll b , total chlorophyll, and carotenoids in the waterlogging-sensitive pumpkins decreased, while those of the waterlogging-tolerant pumpkins increased. Additionally, waterlogging-tolerant pumpkins could maintain a good balance between the synthesis and clearance of reactive oxygen species, with a low degree of membrane lipid peroxidation, and synthesize more chlorophyll to resist waterlogging stress. The waterlogging-tolerant pumpkins mainly underwent ethanol fermentation in the early stages of waterlogging stress, followed by combined ethanol and lactic acid fermentation. However, the waterlogging-sensitive pumpkins mainly underwent lactic acid fermentation in the early stages of waterlogging stress. These findings provide a basis for the research on the waterlogging tolerance mechanism of pumpkins and the selection of the rootstock varieties of edible waterlogging-tolerant pumpkins. [ABSTRACT FROM AUTHOR]

As the main by-product of apple processing, apple pomace should be fully utilized, which was crucial for the quality and efficiency improvement of the whole apple industry. Based on the established subcritical water extraction in the previous study, the apple pomace pectin was successfully extracted in a green and efficient way, which also produced solid residue called de-pectin apple pomace needed to be furtherly utilized. For its main component was lignocellulose, the de-pectin apple pomace was suitable to be transformed to bioethanol. However, the direct ethanol conversion rate of de-pectin apple pomace was low, so the high-efficiency ethanol conversion process was established by optimizing the parameters of pretreatment and enzymatic hydrolysis in the present study. The optimal pretreatment parameters were 180°C (pretreatment temperature), 10 min (pretreatment time), and 1:40 (solid-liquid ratio, g/mL). With the optimal enzyme usage of cellulase (CEL-01) of 5 FPU/g (32.17 mg/g) and β-glucosidase (SPE-007AL) of 1 U/g (34.94 μL/g), the ethanol concentrations of SHF(Separate hydrolysis and fermentation) and SSSF(Semi simultaneous saccharification and fermentation) were 42.48 g/L and 42.50 g/L on a substrate loading of 23% (w/v) and which about Fed-SHF(Fed-batch separate hydrolysis and fermentation) and Fed-SSSF(Fed-batch semi simultaneous saccharification and fermentation) were 57.90 g/L and 66.40 g/L on a substrate loading of 35% (w/v), indicating that de-pectin apple pomace had the excellent potential for industrial ethanol conversion. In addition, for there were some functional components in the residues from transformation process, such as polyphenol and lignin, the pretreatment liquid was fermented by Lactobacillus to develop a functional beverages, which possessed excellent antioxidant activity (more than 90% scavenging activity of DPPH) and more than 108 CFU/mL of viable counts, while solid residues obtained after ethanol fermentation were used to produce chewable tablets for the high content of lignin, which possessed well binding ability of chenodeoxycholic acid of 15 mg/g. Based on the double subcritical water pretreatment, the whole components utilization system of the apple pomace was established. Meanwhile, the mass balance based on 1 kg apple pomace utilization was also analyzed to indicate the detailed substrate transformation process of the whole components utilization system, which was beneficial to resolving the problem of apple pomace utilization in a more feasible way. [Display omitted] • The bioethanol production from apple pomace was efficiently improved by subcritical water pretreatment. • Ethanol concentration reached to 66.40 g/L in Fed-Batch SSSF based on substrate loading of 35% (w/v). • Whole components utilization of de-pectin apple pomace had been realized. • Mass balance of the whole components utilization system had been analyzed. [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]

Sugarcane molasses is one of the main raw materials for bioethanol production, and Saccharomyces cerevisiae is the major biofuel-producing organism. In this study, a batch fermentation model has been used to examine ethanol titers of deletion mutants for all yeast nonessential genes in this yeast genome. A total of 42 genes are identified to be involved in ethanol production during fermentation of sugarcane molasses. Deletion mutants of seventeen genes show increased ethanol titers, while deletion mutants for twenty-five genes exhibit reduced ethanol titers. Two MAP kinases Hog1 and Kss1 controlling the high osmolarity and glycerol (HOG) signaling and the filamentous growth, respectively, are negatively involved in the regulation of ethanol production. In addition, twelve genes involved in amino acid metabolism are crucial for ethanol production during fermentation. Our findings provide novel targets and strategies for genetically engineering industrial yeast strains to improve ethanol titer during fermentation of sugarcane molasses. • Screening 4797 gene mutants for ethanol fermentation titers of sugarcane molasses. • Forty-two genes involved in ethanol production in sugarcane molasses fermentation. • Seventeen mutants show increased, but 25 mutants exhibit reduced, ethanol yields. • Two MAP kinases Hog1 and Kss1 negatively regulate ethanol production. • Amino acid metabolism are crucial for ethanol production during fermentation. [ABSTRACT FROM AUTHOR]

Several lignocellulosic wastes are generated in the pulp and paper industry (PPI), such as small wood chips (pinchips) and paper sludge, presenting a high cellulose content suitable to be converted into biofuels or bio-products in a forest biorefinery scheme. In this work, two schemes of biorefinery were proposed for their valorization, processing small eucalyptus wood pinchips in two different strategies: (i) autohydrolysis at 230ºC, and (ii) autohydrolysis at 195ºC followed by organosolv process (47.7% ethanol-water, 198ºC for 60 min). More than 95% of cellulose was recovered in both schemes. In the combined process, 76% of delignification was achieved and 78% of xylan was solubilized as xylooligosaccharides. To reduce operational cost of lignocellulosic biomass-to-ethanol fermentation, the mixture of the treated eucalyptus pinchips from two processes with sludge was also proposed to increase the initial glucan content and to supply a rich source of nitrogen (present in the sludge). For that, two experimental designs were carried out for ethanol production by simultaneous saccharification and fermentation (SSF) process. Ethanol from SSF assays using sludge as co-substrate at 0.6 g of sludge/g of treated wood pinchips and 16 FPU/g of pretreated solids allowed to obtain 59 g/L (90% of conversion) and 46 g/L (96% of conversion) when blended with the wood from autohydrolysis and with the wood from autohydrolysis followed by organosolv, respectively. Overall, this study shows an alternative process valorization of biomasses derived from PPI for production of advanced biofuels and bio-products (such as xylooligosaccharides and lignin) contributing to achieving a circular economy. • Multi-waste valorization approach was proposed to produce biofuel and bioproducts. • Autohydrolysis and organosolv processes allowed > 90% glucan recoveries. • Higher than 40 g/L of ethanol and 90% of yield were obtained in both schemes developed. • Blending with sludge improve ethanol production from pretreated eucalyptus wood. [ABSTRACT FROM AUTHOR]