Sugar Consumption Rate Research Articles

The Factors Influencing Import of Raw Crystal Sugar From Thailand to Indonesia

This research aims to determine what factors influence the import of raw crystal sugar from Thailand to Indonesia. The method for determining regions is purposively used, namely, in Indonesia. The data collection method used in this research is secondary data. The data analysis method used is a multiple linear regression test with the Ordinary Least Square or OLS method. The results of this research are as follows: (1) The regression model used passed the classical assumption test, namely Multicollinearity, Heteroscedasticity, Autocorrelation, and Normality. (2). Factors that have a significant positive effect on the quantity of imported raw crystal sugar (raw sugar) from Thailand to Indonesia are GDP (gross domestic product) per capita. In contrast, one factor that significantly affects the number of imports of raw crystal sugar (raw sugar) from Thailand to Indonesia is the price of imported sugar. (3). Factors that do not significantly influence the quantity of raw crystal sugar imports from Thailand to Indonesia are sugar import tariffs and consumption rates

Synthetic redesign of Escherichia coli W for faster metabolism of sugarcane molasses

BackgroundSugarcane molasses, rich in sucrose, glucose, and fructose, offers a promising carbon source for industrial fermentation due to its abundance and low cost. However, challenges arise from the simultaneous utilization of multiple sugars and carbon catabolite repression (CCR). Despite its nutritional content, sucrose metabolism in Escherichia coli, except for W strain, remains poorly understood, hindering its use in microbial fermentation. In this study, E. coli W was engineered to enhance sugar consumption rates and overcome CCR. This was achieved through the integration of a synthetically designed csc operon and the optimization of glucose and fructose co-utilization pathways. These advancements facilitate efficient utilization of sugarcane molasses for the production of 3-hydroxypropionic acid (3-HP), contributing to sustainable biochemical production processes.ResultsIn this study, we addressed challenges associated with sugar metabolism in E. coli W, focusing on enhancing sucrose consumption and improving glucose-fructose co-utilization. Through targeted engineering of the sucrose utilization system, we achieved accelerated sucrose consumption rates by modulating the expression of the csc operon components, cscB, cscK, cscA, and cscR. Our findings revealed that monocistronic expression of the csc genes with the deletion of cscR, led to optimal sucrose utilization without significant growth burden. Furthermore, we successfully alleviated fructose catabolite repression by modulating the binding dynamics of FruR with the fructose PTS regulon, enabling near-equivalent co-utilization of glucose and fructose. To validate the industrial applicability of our engineered strain, we pursued 3-HP production from sugarcane molasses. By integrating heterologous genes and optimizing metabolic pathways, we achieved improvements in 3-HP titers compared to previous studies. Additionally, glyceraldehyde-3-phosphate dehydrogenase (gapA) repression aids in carbon flux redistribution, enhancing molasses conversion to 3-HP.ConclusionsDespite limitations in sucrose metabolism, the redesigned E. coli W strain, adept at utilizing sugarcane molasses, is a valuable asset for industrial fermentation. Its synthetic csc operon enhances sucrose consumption, while mitigating CCR improves glucose-fructose co-utilization. These enhancements, coupled with repression of gapA, aim to efficiently convert sugarcane molasses into 3-HP, addressing limitations in sucrose and fructose metabolism for industrial applications.

Bioethanol production from cassava fed-batch fermentation in pervaporation membrane bioreactor with permeate fractional condensation

A new type pervaporation membrane bioreactor was developed by coupling cassava-based fed-batch fermentation and pervaporation membrane separation technology for bioethanol production. Membrane separation slowed down broth accumulation rate and mitigated ethanol product inhibition. The fermentation time, average sugar consumption rate, ethanol production and ethanol productivity were 131h, 6.6 gL-1h-1, 149.4 gL-1 and 2.5 gL-1h-1, respectively. They were improved by 55.9 %, 73.2 %, 32.3 % and 49.7 %, respectively, compared to those of conventional fed-batch fermentation. The average membrane flux and separation factor were 711.3 gm-2h-1 and 6.5, respectively, with an ethanol concentration of 24.4 wt% in the permeate. Throughout fermentation, the total mass transfer coefficient remained constant at 9.6 × 10-6 ms-1, with the convection mass transfer coefficient decreasing as the broth viscosity increasing while the membrane mass transfer coefficient slightly increasing. A two-stage condensation downstream the membrane achieved fractional vapor recovery. The primary condensate with low ethanol concentration (1.6 wt%) can be used for cassava hydrolyzation, saving 14.0 % of water requirement. Recovering ethanol from the high-concentration (32.6 wt%) secondary condensate required lower energy (46 %) compared to direct recovery from the total permeate.

Integrating the Sufficiency Economy Royal Philosophy and Participatory Action Research Approach to Promote Self-Care for Stroke Prevention in Selected Communities of Southern Thailand.

(1) Introduction: Effective control of stroke risk factors can reduce stroke incidence. Motivation for participatory action of community dwellers to practice self-care to modify stroke risk after providing them with knowledge of stroke risk factors is considered useful under a situation of limited healthcare resources. This study aimed to evaluate the outcomes of integrating the sufficiency economy philosophy (SEP), a royal economic philosophy in Thailand, and the participatory action research (PAR) approach on stroke risk factors control among selected communities. (2) Methods: Villagers who had medium to high stroke risk from two provinces with leading stroke incidences in southern Thailand were invited to participate in an eight-month SEP-PAR program conducted in 2019. Group meetings among the study participants, local healthcare providers, the researchers, and relevant stakeholders in the communities were held to co-design a health behaviors program targeting lower waist circumference (WC), body weight (BW), blood pressure (BP), fasting blood sugar, blood lipids, and smoking and alcohol consumption rates. Follow-up physical measurements and blood tests were compared with the baseline results for significant differences by descriptive statistics (p < 0.05) using the R program. (3) Results: Of 126 participants, 75.4% were female. Moderate and high stroke risk levels were found in 58.2% and 19.8%, respectively. Elevated baseline WC, BW, BP, and blood test results were found in 50-80% of the participants. The co-designed health behaviors in this study were dietary control, regular exercise, relieving psychological stress, and stopping smoking and alcohol consumption. Overall, the participants had significant adherence to the co-designed health behaviors. At the end of the program, the follow-up tests showed significant reductions in BW, BP, fasting blood sugar, and lipids, but not in WC. (4) Conclusions: A combined SEP and PAR approach was effective for stroke risk factors control among the community dwellers. Motivation for self-care is a significant strategic outcome expected of this approach. Longer follow-up studies in larger populations are needed.

Extensive remodeling of sugar metabolism through gene loss and horizontal gene transfer in a eukaryotic lineage

BackgroundIn yeasts belonging to the subphylum Saccharomycotina, genes encoding components of the main metabolic pathways, like alcoholic fermentation, are usually conserved. However, in fructophilic species belonging to the floral Wickerhamiella and Starmerella genera (W/S clade), alcoholic fermentation was uniquely shaped by events of gene loss and horizontal gene transfer (HGT).ResultsBecause HGT and gene losses were first identified when only eight W/S-clade genomes were available, we collected publicly available genome data and sequenced the genomes of 36 additional species. A total of 63 genomes, representing most of the species described in the clade, were included in the analyses. Firstly, we inferred the phylogenomic tree of the clade and inspected the genomes for the presence of HGT-derived genes involved in fructophily and alcoholic fermentation. We predicted nine independent HGT events and several instances of secondary loss pertaining to both pathways. To investigate the possible links between gene loss and acquisition events and evolution of sugar metabolism, we conducted phenotypic characterization of 42 W/S-clade species including estimates of sugar consumption rates and fermentation byproduct formation. In some instances, the reconciliation of genotypes and phenotypes yielded unexpected results, such as the discovery of fructophily in the absence of the cornerstone gene (FFZ1) and robust alcoholic fermentation in the absence of the respective canonical pathway.ConclusionsThese observations suggest that reinstatement of alcoholic fermentation in the W/S clade triggered a surge of innovation that goes beyond the utilization of xenologous enzymes, with fructose metabolism playing a key role.

Sociocultural determinants of children's oral health among immigrants in Canada.

A conceptual model was designed and tested to predict immigrant children's oral health in Canada by examining parental acculturation and perceived social support (PSS) using structural equation modelling. A convenience sample of first-generation immigrant parents and their children aged 2-12 years were recruited by multilingual community workers in Edmonton, Canada. Parents completed a validated questionnaire on demographics, child's oral health (OH) behaviours, parental acculturation and PSS. Dental examinations determined children's dental caries rate using DMFT/dmft index. Structural equation modelling (SEM) was used to analyse the data. A total of 336 families participated in this study. The average parental acculturation level was 10.46 with a maximum of 15, and the average PSS was 63.27 with a maximum of 75. SEM showed that 77% of the variance of DMFT/dmft scores in children was explained by parental PSS, acculturation level, immigration-related variables, socioeconomic variables and children's OH behaviours. The direct effect of parental PSS was associated with a significantly reduced rate of dental caries (β = -.076, p-value = .008) and lower sugar consumption (β = -.17, p-value = .04). While the mediation effect of parental acculturation on PSS was associated with positive OH behaviours of children (e.g., toothbrushing frequency and dental care utilization), the indirect effect was negatively associated with caries rate (β = .77, p-value = .00). The direct effect of Parental Perceived Stress Scale (PSS) was associated with more favourable oral health behaviours and a lower prevalence of dental caries, while the mediation effect of acculturation was linked to a higher prevalence of dental caries.

A Comparative Analysis of Bacterial Diversity in Individuals Exhibiting Oral Cavity Disorders versus those in a State of Oral Health

Oral cavity is considered as main entrance of the body and our mouth encounters a large number of microorganisms from the outer environment, some of which have the potential to cause serious illnesses. Current study was designed to evaluate different ecological and behavioral factors which can positively or negatively affect normal flora of oral cavity. Behavioral information was gathered through personal interviews from 90 study subjects, out of which 45 were included in control group without any current oral disorders and other 45 were included in experimental group with current oral diseases. High rate of sugar consumption, low brushing frequency, over-use of medications, acidic food consumption, high rate of smoking, aggressive mode of brushing and lack of awareness about dental health were some of the factors observed in a higher ratio in experimental group. These behaviours can aggravate oral problems causing imbalances in normal flora of oral cavity. It was also noted that frequency of systemic diseases was higher in experimental group, and it was due to the fact that unbalanced bacterial oral flora can gain entry into blood through bacteraemia and travel to different organs, thus, intensifying systemic issues. A comparative analysis was also made between bacterial flora of healthy controls and oral patients. A total of 34 oral samples, 17 from control group and 17 from experimental group, were collected and analyzed morphologically and biochemically. A total of 12 distinct bacterial species were isolated from these collected samples. Some of the species were conserved in both groups but were present in varying proportions. But Neisseria spp. was isolated only from healthy controls while Escherichia coli, Pseudomonas aeruginosa, Corynebacterium and Actinobacteria were isolated from samples oral patients. The most abundant species in healthy controls were Staphylococcus aureus, Lactobacilli and Staphylococcus epidermidis while in oral patients were Lactococci, Actinobacteria, Corynebacterium and Streptococcus viridans group. The involvement of oral bacterial flora in systemic diseases and role of behavioral elements in aggravating oral diseases was also responsible for oral cavity disorders. Different pathogenic bacteria can alter the natural bacterial ecology of oral cavity, aggravating oral diseases. This study may provide a baseline data to develop different strategies to control pathogenic oral flora

Bioethanol production from cassava fermentation in pervaporation membrane bioreactor fed with high concentration sugar

Bioethanol production from cassava in a pervaporation membrane bioreactor consisted of fermentation coupled with polydimethylsiloxane (PDMS) membrane separation has been carried out. A cassava hydrolysate with a high sugar concentration of 448–492 gL-1 was prepared by repeating the liquefaction process and then fed to the bioreactor to overcome the fermentation broth volume expansion problem. The coupled system lasted as long as 248 h. The cell concentration, sugar consumption rate, ethanol productivity, and total ethanol production were 22 gL-1, 3.91 gL-1h−1, 1.47 gL-1h−1, and 365.1 gL-1, respectively. The average membrane flux and separation factors of the membrane were 645 gm-2h−1 and 5.3, respectively. A permeate vapor with as high as 21.5 wt% ethanol concentration downstream of the membrane was obtained. Fractional condensation was used downstream of the membrane to differentially refine and recover the ethanol from the permeate vapor. The ethanol concentration can be increased by 57.3 % with the fractional condensation method, with separation factor increased to 9.8–14.9. As much as 96.6 % of the permeated ethanol on the downstream of the membrane can be recovered as the product with high ethanol concentration.

Evaluation of different nitrogen sources on growth and fermentation performance for enhancing ethanol production by wine yeasts

The utilization of grape juice from low oenological value grape varieties for bioethanol production represent an alternative for diversification and value addition in viticulture. Optimizing Very High Gravity (VHG) fermentation can significantly increase ethanol productivity while reducing water and energy consumption. In this study, the impact of different nitrogen sources on growth and fermentative performance of locally selected yeast strains was investigated. Five yeast strains of species Saccharomyces cerevisiae and Zygosaccharomyces rouxii were cultured in both synthetic culture media and natural grape juice supplemented with ammonium sulfate (NH), yeast extract (YE), Fermaid K (FERM), and urea (U) at varying concentrations. Due to the very low fermentation rate, the Z. rouxii strain was excluded from the selection. The results obtained in synthetic medium showed that nitrogen sources that promoted growth (NH and YE) had minimal effects on fermentative performance and were highly dependent on the specific yeast strain. However, the combination of urea and ammonium favored the rate of sugar consumption. When validated in natural grape juice, urea combined with ammonium (U + NH 300 + 75 mg/L) improved both growth parameters and ethanol yield. Doubling the concentration (U + NH 600 + 150 mg/L) further enhanced sugar consumption and ethanol production while reducing unwanted by-products. The combined use of urea and ammonium exhibited a synergistic effect, making it a cost-effective nitrogen supplement for VHG fermentations.

Synergistic co-utilization of biomass-derived sugars enhances aromatic amino acid production by engineered Escherichia coli.

Efficient co-utilization of mixed sugar feedstocks remains a biomanufacturing challenge, thus motivating ongoing efforts to engineer microbes for improved conversion of glucose-xylose mixtures. This study focuses on enhancing phenylalanine production by engineering Escherichia coli to efficiently co-utilize glucose and xylose. Flux balance analysis identified E4P flux as a bottleneck which could be alleviated by increasing the xylose-to-glucose flux ratio. A mutant copy of the xylose-specific activator (XylR) was then introduced into the phenylalanine-overproducing E. coli NST74, which relieved carbon catabolite repression and enabled efficient glucose-xylose co-utilization. Carbon contribution analysis through 13 C-fingerprinting showed a higher preference for xylose in the engineered strain (NST74X), suggesting superior catabolism of xylose relative to glucose. As a result, NST74X produced 1.76 g/L phenylalanine from a model glucose-xylose mixture; a threefold increase over NST74. Then, using biomass-derived sugars, NST74X produced 1.2 g/L phenylalanine, representing a 1.9-fold increase over NST74. Notably, and consistent with the carbon contribution analysis, the xylR* mutation resulted in a fourfold greater maximum rate of xylose consumption without significantly impeding the maximum rate of total sugar consumption (0.87 vs. 0.70 g/L-h). This study presents a novel strategy for enhancing phenylalanine production through the co-utilization of glucose and xylose in aerobic E. coli cultures, and highlights the potential synergistic benefits associated with using substrate mixtures over single substrates when targeting specific products.

Structural characterization of alkali-extracted jujube polysaccharides and their effects on the fecal microbiota in vitro

The structural characteristics of alkali-extracted jujube polysaccharides and their effects of in vitro fermentation on fecal microorganisms were evaluated in this study. Scanning electron microscopy revealed that AJP1 and AJP2 polysaccharides had different morphological characteristics, and their molecular weights were 75465 Da and 268007 Da, respectively. The uronic acid contents of the two polysaccharides were 79.68% and 77.64%. Infrared spectroscopy showed that two alkaline-extracted polysaccharide groups had characteristic absorption peaks of acidic polysaccharides such as C=O and C-H. After 48 h of in vitro fermentation, the total sugar consumption rates of the AJP1 and AJP2 treatments reached 65.40% and 56.24%, respectively. During the fermentation process, the pH values of the polysaccharide-treated groups were significantly lower compared to the control group. In addition, polysaccharides could promote the abundance, diversity, and composition of gut microbiota. These results showed that alkali-extracted jujube polysaccharides could regulate the intestinal microflora composition in feces, and inhibit the growth of pathogenic bacteria Peptoniphilus and Desulfovibrio while promoting the growth of beneficial bacteria such as Megamonas and Allisonella. This study provides a reference for further developing jujube polysaccharide functional food products and the study of the structure-activity relationship between alkali-extracted polysaccharides and intestinal flora.

Effects of Selenium Enrichment on Dough Fermentation Characteristics of Baker's Yeast.

In this research, the effect of selenium (Se) enrichment on dough fermentation characteristics of yeast and the possible mechanisms was investigated. Then, the Se-enriched yeast was used as starter to make Se-enriched bread, and the difference between Se-enriched bread and common bread was investigated. It was found Se enrichment increased CO2 production and sugar consumption rate of Saccharomyces cerevisiae (S. cerevisiae) in dough fermentation, and had positive impacts on final volume and rheological index of dough. The mechanism is possibly related to higher activity and protein expression of hexokinase (HK), phosphofructokinase (PFK), pyruvate kinase (PK), citrate synthase (CS), isocitrate dehydrogenase (ICD), and α-ketoglutarate dehydrogenase (α-KGDHC) in Se-enriched yeast. Moreover, Se-enriched bread (Se content: 11.29 μg/g) prepared by using Se-enriched yeast as starter exhibited higher overall acceptability on sensory, cell density in stomatal morphology, and better elasticity and cohesiveness on texture properties than common bread, which may be due to effect of higher CO2 production on dough quality. These results indicate Se-enriched yeast could be used as both Se-supplements and starter in baked-foods making.

Effect of DAP and glutamine supplementation on sulfur-containing volatiles and sensory properties of Chardonnay wine fermented with Saccharomyces cerevisiae yeast.

Volatile compounds in wine have a critical impact on the consumers' senses. In this study, the effect of diammonium phosphate (DAP) and glutamine on sulfur-containing volatiles and sensory properties of Chardonnay wine fermented with Saccharomyces cerevisiae yeast were evaluated. Fermentation kinetics was determined by monitoring reducing sugar consumption rates during fermentation. The volatile profile of wines was analyzed by headspace solid phase microextraction (HS-SPME) coupled with gas-chromatography-mass spectrometry (GC-MS). The volatile sulfur compounds (VSCs) were analyzed by HS-SPME-GC-MS/MS. Flavor attributes of wines were assessed by a sensory panel with quantitative descriptive analysis. A total of 53 volatiles, including 6 VSCs, were identified and quantified in the Chardonnay wine. The results suggested that glutamine supplementation at the beginning of fermentation could help to initiate fermentation earlier and promote the formation of isoamyl acetate, phenethyl acetate, ethyl nonanoate, methyl decanoate, diethyl succinate and phenethyl alcohol, isobutanol, while DAP supplementation had no obvious effect on the volatile composition of the resulting wine and fermentation kinetics. PRACTICAL APPLICATION: Suitable nitrogen source is helpful to a healthy fermentation, and can also prevent the off-flavor and regulate aroma profile of wine. This study provides insights on the volatile and sensory characteristics of Chardonnay wines affected by different nitrogen source addition.

Split batch and coculture fermentation to regulate the organic acids and flavor profile of fruit wine-a case study of Prunus mume Sieb. et Zucc (greengage) wine

The higher acidity in fruits compared with grapes was one of the main obstacles to producing high-quality fruit wines. In the present research, the effect of the split batch fermentation pattern on the metabolites of greengage wines was investigated. This fermentation pattern included whole fruit immersion in the sucrose and coculturing Saccharomyces bayanus Y4 with Torulaspora delbrueckii Y7. These results showed that the contents of total acidity and dominant organic acids were significantly reduced among the batches. Aliphatic compounds were decreased with the batches, while aromatic compounds that contributed to flavor improvement were increased oppositely. The acetate esters, ketones, and terpenes contents were significantly increased in the first batch of coculture. In addition, acidic stress largely affected the kinetics characteristics of greengage wine on a pilot scale. Interestingly, the increment of total acidity was closely associated with the rate of total sugar consumption, which was affected by microbial activities. The acidity content was significantly declined and distinct flavour profiles were formed in split batch and coculture fermentation of greengage wines. It provides a new avenue to enhance the flavor and quality of fruit wines.

Zymo-Parts: A Golden Gate Modular Cloning Toolbox for Heterologous Gene Expression in Zymomonas mobilis.

Zymomonas mobilis is a microorganism with extremely high sugar consumption and ethanol production rates and is generally considered to hold great potential for biotechnological applications. However, its genetic engineering is still difficult, hampering the efficient construction of genetically modified strains. In this work, we present Zymo-Parts, a modular toolbox based on Golden-Gate cloning offering a collection of promoters (including native, inducible, and synthetic constitutive promoters of varying strength), an array of terminators and several synthetic ribosomal binding sites and reporter genes. All these parts can be combined in an efficient and flexible way to achieve a desired level of gene expression, either from plasmids or via genome integration. Use of the GoldenBraid-based system also enables an assembly of operons consisting of up to five genes. We present the basic structure of the Zymo-Parts cloning system, characterize several constitutive and inducible promoters, and exemplify the construction of an operon and of chromosomal integration of a reporter gene. Finally, we demonstrate the power and utility of the Zymo-Parts toolbox for metabolic engineering applications by overexpressing a heterologous gene encoding for the lactate dehydrogenase of Escherichia coli to achieve different levels of lactate production in Z. mobilis.

Enhanced tolerance of Cupriavidus necator NCIMB 11599 to lignocellulosic derived inhibitors by inserting NAD salvage pathway genes.

Polyhydroxybutyrate (PHB) is a bio-based, biodegradable and biocompatible plastic that has the potential to replace petroleum-based plastics. Lignocellulosic biomass is a promising feedstock for industrial fermentation to produce bioproducts such as polyhydroxybutyrate (PHB). However, the pretreatment processes of lignocellulosic biomass lead to the generation of toxic byproducts, such as furfural, 5-HMF, vanillin, and acetate, which affect microbial growth and productivity. In this study, to reduce furfural toxicity during PHB production from lignocellulosic hydrolysates, we genetically engineered Cupriavidus necator NCIMB 11599, by inserting the nicotine amide salvage pathway genes pncB and nadE to increase the NAD(P)H pool. We found that the expression of pncB was the most effective in improving tolerance to inhibitors, cell growth, PHB production and sugar consumption rate. In addition, the engineered strain harboring pncB showed higher PHB production using lignocellulosic hydrolysates than the wild-type strain. Therefore, the application of NAD salvage pathway genes improves the tolerance of Cupriavidus necator to lignocellulosic-derived inhibitors and should be used to optimize PHB production.

Adaptation on xylose improves glucose–xylose co-utilization and ethanol production in a carbon catabolite repression (CCR) compromised ethanologenic strain

BackgroundSugar hydrolysates from lignocellulosic biomass are majorly composed of glucose and xylose that can be fermented to biofuels. Bacteria, despite having the natural ability to consume xylose are unable to consume it in presence of glucose due to a carbon catabolite repression (CCR) mechanism. This leads to overall reduced productivity as well as incomplete xylose utilization due to ethanol build-up from glucose utilization. In our effort to develop a strain for simultaneous fermentation of glucose and xylose into ethanol, we deleted ptsG in ethanologenic E. coli SSK42 to make it deficient in CCR and performed adaptive laboratory evolution to achieve accelerated growth rate, sugar consumption and ethanol production. Finally, we performed proteomics study to identify changes that might have been responsible for the observed improved phenotype of the evolved strain.ResultsThe parental strain of SSK42, i.e., wild-type E. coli B, did not co-utilize glucose and xylose as expected. After deleting the ptsG gene encoding the EIIBCGlc subunit of PTS system, glucose consumption is severely affected in wild-type E. coli B. However, the ethanologenic, SSK42 strain, which was evolved in our earlier study on both glucose and xylose, didn’t show such a drastic effect of EIIBCGlc deletion, instead consumed glucose first, followed by xylose without delay for switching from one sugar to another. To improve growth on xylose and co-utilization capabilities, the ptsG deleted SSK42 was evolved on xylose. The strain evolved for 78 generations, strain SCD78, displayed significant co-utilization of glucose and xylose sugars. At the bioreactor level, the strain SCD78 produced 3-times the ethanol titer of the parent strain with significant glucose–xylose co-utilization. The rate of glucose and xylose consumption also increased 3.4-fold and 3-fold, respectively. Proteome data indicates significant upregulation of TCA cycle proteins, respiration-related proteins, and some transporters, which may have a role in increasing the total sugar consumption and co-utilization of sugars.ConclusionThrough adaptive evolution, we have obtained a strain that has a significant glucose–xylose co-utilization phenotype with 3-fold higher total sugar consumption rate and ethanol production rate compared to the unevolved strain. This study also points out that adaptation on xylose is enough to impart glucose–xylose co-utilization property in CCR compromised ethanologenic strain SSK42.

Fermentation of Dairy-Relevant Sugars by Saccharomyces, Kluyveromyces, and Brettanomyces: An Exploratory Study with Implications for the Utilization of Acid Whey, Part II

In Greek-style yogurt production, every kilogram of product yields 2 to 3 kg of acid whey (YAW); this coproduct’s composition and low pH pose challenges for its proper valorization and reinsertion into the food supply chain. However, 240 mL of YAW contains over 9 g of lactose and represents a good source of minerals; these traits can be leveraged to develop nutritious fermented beverages. The purpose of this study is to investigate the aerobic fermentation of dairy sugars by different yeasts by characterizing these processes and their products. This will determine whether such methods provide viable options for the production of acetic-acid-containing beverages from YAW. To achieve this, yeast nitrogen base was used to prepare four growth media formulations, each supplemented with lactose, glucose, galactose, or a 1:1 mix of glucose and galactose (GLU:GAL), and each adjusted to a pH of 4.20. Fermentations were performed by pure cultures of S. cerevisiae, K. marxianus, B. claussenii, or B. bruxellensis, and were held at 25 °C with agitation at 185 rpm. For each treatment, density, pH, and microbial enumeration were measured over time to obtain process profiles, while ethanol, organic acids, and sugars were analyzed at the beginning and the end of each fermentation via HPLC, to determine resulting products. ANOVA and Tukey’s honest significant difference test at a significance level of 0.05 were used to compare residual sugars and fermentation products. Variable rates of sugar consumption were observed for each species. In GLU:GAL, B. claussenii consumed all of the glucose, left behind most of the galactose, and produced a high concentration of acetic acid. These results suggest the potential to develop versatile processes that target glucose for acetic acid production, while leaving available galactose to confer products with prebiotic properties. The development of processes for the conversion of YAW into beverages with organic acids and other healthful components not only aligns with consumers’ demands for better-for-you products, but also promotes the valorization of this otherwise underutilized dairy coproduct.

Enzymatic Biocatalysis of Biomass from Aquatic Plant Phragmite Karka for Second-Generation Bioethanol Production

In the context of energy transition and the reduction of greenhouse gas emissions, the production of second-generation bioethanol is also recognized as a promising way to reduce our dependence on fossil fuels. Then, the present studies aim to evaluate the enzymatic biocatalysis of biomass from aquatic plant Phragmite karka in the second-generation bioethanol production. Results obtained revealed a rapid decrease of °Brix during the fermentation of musts and underlined the efficacy of enzyme hydrolysis. The rate of sugar consumption by yeasts is between 32.43 and 70.27%. The yield of ethanol production of yeasts indicated that Angel Brand Thermal-tolerant alcohol active dry yeast was the best yeast strain for this fermentation. These findings underline the potential of Phragmite karka plant materials in the perspective of intensive production of second-generation bioethanol.

In vitro Digestion and Fermentation Characteristics of Polysaccharides from Camellia nitidissima Chi

Polysaccharides were isolated from Camellia nitidissima Chi by water extraction and alcohol precipitation, then the polysaccharide extract was separated and purified by using DEAE-52 cellulose chromatography column. The digestion characteristics of the polysaccharides were studied in vitro by employing a simulated upper gastrointestinal model and analyzing molecular weight, reducing sugar and free monosaccharide ontents of digested products at different digestion times. The fermentation characteristics of polysaccharides were studied in vitro by using human fecal fermentation model and analyzing pH, total sugar, reducing sugar and short chain fatty acid content ,as well as the Lactobacillus, Bifidobacterium and Escherichia coli number. The results showed that, TPS1, TPS2, and TPS3 were obtained after purification of the polysaccharide from Camellia nitidissima Chi. During in vitro digestion, the molecular weight of TPS1, TPS2, TPS3 and the reducing sugar content did not changed by simulated saliva and simulated intestinal juice. Simulated gastric juice caused a slight decrease in the molecular weight of TPS1, TPS2, and TPS3, and the content of reducing sugar increased from 0.129±0.016, 0.155±0.026, 0.147±0.017 mmol/L to 0.223±0.018, 0.319±0.013, 0.294±0.030 mmol/L. Free monosaccharides were not detected during the digestion. During the fermentation process, the pH of the group added with TPS1, TPS2, and TPS3 was significantly lower than that of the blank control group, the sugar consumption rate was 91.4%, 89.0%, 94.5%, and the reducing sugar content increased during 0~18 h, reduced during 18~48 h; Compared with the blank control group, the levels of acetic acid, propionic acid, and butyric acid were all significantly increased and the order of increasing multiple size was TPS3>TPS2>TPS1. Further, TPS1, TPS2 and TPS3 could promote the growth of Lactobacillus and Bifidobacterium, inhibit the growth of Escherichia coli, and the order of probiotic effects was TPS3>TPS2>TPS1. In summary, the polysaccharides were isolated from Camellia nitidissima Chi were not digested in vitro, and could be used by fecal microflora to produce a large amount of acetic acid, propionic acid and butyric acid, which had potential probiotic effects. And TPS3 had better probiotic effects than TPS2 and TPS1.