Comparative Transcriptomic Analysis Revealing the Potential Mechanisms of Erythritol-Caused Mortality and Oviposition Inhibition in Drosophila melanogaster.

Erythritol has shown excellent insecticidal performance against a wide range of insect species, but the molecular mechanism by which it causes insect mortality and sterility is not fully understood. The mortality and sterility of Drosophila melanogaster were assessed after feeding with 1M erythritol for 72 h and 96 h, and gene expression profiles were further compared through RNA sequencing. Enrichment analysis of GO and KEGG revealed that expressions of the adipokinetic hormone gene (Akh), amylase gene (Amyrel), α-glucosidase gene (Mal-B1/2, Mal-A1-4, Mal-A7/8), and triglyceride lipase gene (Bmm) were significantly up-regulated, while insulin-like peptide genes (Dilp2, Dilp3 and Dilp5) were dramatically down-regulated. Seventeen genes associated with eggshell assembly, including Dec-1 (down 315-fold), Vm26Ab (down 2014-fold) and Vm34Ca (down 6034-fold), were significantly down-regulated or even showed no expression. However, there were no significant differences in the expression of three diuretic hormone genes (DH44, DH31, CAPA) and eight aquaporin genes (Drip, Big brain, AQP, Eglp1, Eglp2, Eglp3, Eglp4 and Prip) involved in osmolality regulation (all p value > 0.05). We concluded that erythritol, a competitive inhibitor of α-glucosidase, severely reduced substrates and enzyme binding, inhibiting effective carbohydrate hydrolysis in the midgut and eventually causing death due to energy deprivation. It was clear that Drosophila melanogaster did not die from the osmolality of the hemolymph. Our findings elucidate the molecular mechanism underlying the mortality and sterility in Drosophila melanogaster induced by erythritol feeding. It also provides an important theoretical basis for the application of erythritol as an environmentally friendly pesticide.

Metabolic Effects of Selected Conventional and Alternative Sweeteners: A Narrative Review.

Sugar consumption is known to be associated with a whole range of adverse health effects, including overweight status and type II diabetes mellitus. In 2015, the World Health Organization issued a guideline recommending the reduction of sugar intake. In this context, alternative sweeteners have gained interest as sugar substitutes to achieve this goal without loss of the sweet taste. This review aims to provide an overview of the scientific literature and establish a reference tool for selected conventional sweeteners (sucrose, glucose, and fructose) and alternative sweeteners (sucralose, xylitol, erythritol, and D-allulose), specifically focusing on their important metabolic effects. The results show that alternative sweeteners constitute a diverse group, and each substance exhibits one or more metabolic effects. Therefore, no sweetener can be considered to be inert. Additionally, xylitol, erythritol, and D-allulose seem promising as alternative sweeteners due to favorable metabolic outcomes. These alternative sweeteners replicate the benefits of sugars (e.g., sweetness and gastrointestinal hormone release) while circumventing the detrimental effects of these substances on human health.

[Advances in efficient biosynthesis of erythritol by metabolic engineering of Yarrowia lipolytica].

Erythritol is a novel 4-carbon sugar alcohol produced by microbes in the presence of hyper-osmotic stress. It has excellent potential to serve as an alternative sugar for people with diabetes and also a platform compound for synthesizing various C4 compounds, such as 1, 3-butadiene, 1, 4-butanediol, 2, 5-dihydrofuran and so on. Compared with other polyols, the fermentative production of erythritol is more challenging. Yarrowia lipolytica is the preferred chassis of erythritol biosynthesis for its high-titer and high-productivity. At present, there are still some bottlenecks in the production of erythritol by Y. lipolytica, such as weak metabolic activity, abundant by-products, and low industrial attributes. Progress has been made in tailoring high version strains according to industrial needs. For example, the highest titer of erythritol produced by the metabolically engineered Y. lipolytica reached 196 g/L and 150 g/L, respectively, by using glucose or glycerol as the carbon sources. However, further improving its production performance becomes challenging. This review summarizes the research progress in the synthesis of erythritol by Y. lipolytica from the perspectives of erythritol producing strains, metabolic pathways, modular modifications, and auxiliary strategies to enhance the industrial properties of the engineered strain. Key nodes in the metabolic pathway and their combination strategies are discussed to guide the research on promoting the production of erythritol by Y. lipolytica.

Transcriptome analysis reveals multiple targets of erythritol-related transcription factor EUF1 in unconventional yeast Yarrowia Lipolytica.

BACKGROUND: Erythritol is a four-carbon polyol with an unclear role in metabolism of some unconventional yeasts. Its production has been linked to the osmotic stress response, but the mechanism of stress protection remains unclear. Additionally, erythritol can be used as a carbon source. In the yeast Yarrowia lipolytica, its assimilation is activated by the transcription factor Euf1. The study investigates whether this factor can link erythritol to other processes in the cell. RESULTS: The research was performed on two closely related strains of Y. lipolytica: MK1 and K1, where strain K1 has no functional Euf1. Cultures were carried out in erythritol-containing and erythritol-free media. Transcriptome analysis revealed the effect of Euf1 on the regulation of more than 150 genes. Some of these could be easily connected with different aspects of erythritol assimilation, such as: utilization pathway, a new potential isoform of transketolase, or polyol transporters. However, many of the upregulated genes have never been linked to metabolism of erythritol. The most prominent examples are the degradation pathway of branched-chain amino acids and the glyoxylate cycle. The high transcription of genes affected by Euf1 is still dependent on the erythritol concentration in the medium. Moreover, almost all up-regulated genes have an ATGCA motif in the promoter sequence. CONCLUSIONS: These findings may be particularly relevant given the increasing use of erythritol-induced promoters in genetic engineering of Y. lipolytica. Moreover, use of this yeast in biotechnological processes often takes place under osmotic stress conditions. Erythritol might be produce as a by-product, thus better understanding of its influence on cell metabolism could facilitate processes optimization.

Adaptive responses of erythritol-producing Yarrowia lipolytica to thermal stress after evolution.

Elucidation of the thermotolerance mechanism of erythritol-producing Yarrowia lipolytica is of great significance to breed robust industrial strains and reduce cost. This study aimed to breed thermotolerant Y. lipolytica and investigate the mechanism underlying the thermotolerant phenotype. Yarrowia lipolytica HT34, Yarrowia lipolytica HT36, and Yarrowia lipolytica HT385 that were capable of growing at 34 °C, 36 °C, and 38.5 °C, respectively, were obtained within 150 days (352 generations) by adaptive laboratory evolution (ALE) integrated with 60Co-γ radiation and ultraviolet ray radiation. Comparative genomics analysis showed that genes involved in signal transduction, transcription, and translation regulation were mutated during adaptive evolution. Further, we demonstrated that thermal stress increased the expression of genes related to DNA replication and repair, ceramide and steroid synthesis, and the degradation of branched amino acid (BCAA) and free fatty acid (FFA), while inhibiting the expression of genes involved in glycolysis and the citrate cycle. Erythritol production in thermotolerant strains was remarkably inhibited, which might result from the differential expression of genes involved in erythritol metabolism. Exogenous addition of BCAA and soybean oil promoted the growth of HT385, highlighting the importance of BCAA and FFA in thermal stress response. Additionally, overexpression of 11 out of the 18 upregulated genes individually enabled Yarrowia lipolytica CA20 to grow at 34 °C, of which genes A000121, A003183, and A005690 had a better effect. Collectively, this study provides novel insights into the adaptation mechanism of Y. lipolytica to thermal stress, which will be conducive to the construction of thermotolerant erythritol-producing strains. KEY POINTS: • ALE combined with mutagenesis is efficient for breeding thermotolerant Y. lipolytica • Genes encoding global regulators are mutated during thermal adaptive evolution • Ceramide and BCAA are critical molecules for cells to tolerate thermal stress.

Diuresis and α-glucosidase inhibition by erythritol in Aedes aegypti (Diptera: Culicidae) and viability for efficacy against mosquitoes.

BACKGROUND: Sugar alcohols, such as erythritol, are low-impact candidates for attractive toxic sugar baits (ATSB) to kill mosquitoes. To determine whether erythritol has a viable future in ATSB formulations, a suite of assays was conducted to diagnose toxicity mechanisms and starvation effects on mortality in Aedes aegypti (L.) as a model system. METHODS: We measured general carbohydrate load, glucosidase levels, and free glucose in intoxicated adult mosquitoes to observe whether sugar digestion was impaired. We assayed the effects of sugar combinations with erythritol on larvae and adults. To measure erythritol effects when mosquitoes were not resource-deprived, additional assays manipulated the prior starvation status. RESULTS: Up to 50,000 ppm of erythritol in water had no effect on larvae within 72 h, but an ammonia spike indicated diuresis in larvae as early as 4 h (F8,44 = 22.50, P < 0.0001) after sucrose/erythritol combinations were added. Adult consumption of erythritol was diuretic regardless of the sugar pairing, while sucrose and erythritol together generated above 80% mortality (F2,273 = 33.30, P < 0.0001) alongside triple the normal excretion (F5,78 = 26.80, P < 0.0004). Glucose and fructose paired individually with erythritol had less mortality, but still double the fecal excretion. When ingesting erythritol-laced meals, less sugar was detected in mosquitoes as compared to after sucrose meals (χ2 = 12.54, df = 1, P = 0.0004). CONCLUSIONS: Data showed that erythritol is a linear competitive inhibitor of α-glucosidase, marking it as a novel class of insecticide in the current research climate. However, the efficacy on larvae was null and not persistent in adult mosquitoes when compared across various starvation levels. Despite significant diuresis, the combined effects from erythritol are not acute enough for vector control programs considering ATSB against mosquitoes.

Visualized sensing of erythritol using a simple enzyme-free catechol-based hydrogel film.

Based on the versatile properties of bio-derived materials, non-enzymatic assays in combination with electronic devices have attracted increasing interest. Here, we report a novel enzyme-free visualization approach for the detection of erythritol, which is a zero-calorie natural sweetener and serves as an ideal sucrose substitute for diabetics or overweight people who need sugar control. The recognition element of the electrochemical biosensor was constructed by catechol modification on a chitosan-based hydrogel film. The signal transduction was achieved by the competitive binding assay of sweeteners. The results show that 2-fluorophenylboronic acid (FPBA) can form a cyclic boronate ester with the ortho-hydroxyls of both reduced catechol and oxidized quinone, impeding the electron transfer and leading to redox signal attenuation. The addition of sweeteners caused a competitive reaction resulting in bonding between the 1,2-diols and FPBA moieties, and in the recovery of the redox signals. Importantly, the pattern of redox signal changes of catechol can be detected optically, as the oxidized quinone state is darker in color than the reduced catechol state. Using a simple cell phone imaging application, we demonstrate that erythritol can be distinguished from other sweeteners in real samples using the oxidized catechol-Chit0/agarose hydrogel film. Thus, we envision that this method could allow diabetics and people who need to control their sugar intake to detect whether the product contains only erythritol in the field or at home. In addition, this work further illustrates the potential of bio-derived materials for performing redox-based functions and enzyme-free visualization assays.

The use of blackcurrant pomace and erythritol to optimise the functional properties of shortbread cookies.

As a result of the production of blackcurrant juice, pomace is produced, which is a cheap, easy to further process raw material with high health benefits. The aim of the research was to develop a recipe for shortbread cookies based on blackcurrant pomace (0, 10, 30, 50%) and erythritol, and to assess their nutritional value (content of proteins, fats, sugars, dietary fibre, selected minerals and energy value), pro-health properties (antioxidant and anti-diabetic capacity) and sensory evaluation. The energy value of products with 50% of pomace sweetened with erythritol was nearly 30% lower compared to traditional cookies, while the content of dietary fibre was 10 times higher in products with the highest percentage of pomace. The antioxidant capacity and the total content of polyphenolic compounds increased with the increase in pomace content. The ability to inhibit α-amylase by shortbread cookies without pomace was about 400 times lower than those with 50% pomace. The results of the sensory evaluation showed that erythritol-sweetened cookies have more desirable characteristics compared to sucrose-sweetened cookies. Finally, it was proved that the proposed products are an excellent proposal for people struggling with food-dependent diseases, as well as being an opportunity to manage waste from the fruit industry.

Application of New Yarrowia lipolytica Transformants in Production of Citrates and Erythritol from Glycerol.

Citric acid and erythritol are obtained on an industrial scale using biotechnological methods. Due to the growing market demand for these products, research is underway to improve the process economics by introducing new microorganisms, in particular of the species Yarrowia lipolytica. The aim of this study was to evaluate transformants of Y. lipolytica for growth and ability to overproduce citric acids and erythritol from glycerol. The transformants were constructed by overexpressing glycerol kinase, methylcitrate synthase and mitochondrial succinate-fumarate transporter in the mutant Wratislavia 1.31. Next, strains were assessed for biosynthesis of citrate (pH 5.5; nitrogen limitation) and erythritol (pH 3.0; high osmotic pressure) from glycerol. Regardless of culture conditions strains, 1.31.GUT1/6 and 1.31.GUT1/6.CIT1/3 exhibited high rates of substrate utilization. Under conditions favoring citrate biosynthesis, both strains produced several percent more citrates, accompanied by higher erythritol production compared to the parental strain. During erythritol biosynthesis, the strain 1.31.GUT1/6.CIT1/3.E34672g obtained as a result of co-expression of all three genes stood out, producing 84.0 g/L of erythritol with yield and productivity of 0.54 g/g and 0.72 g/Lh, respectively, which places it in the group of the highest-ranked producers of erythritol among Y. lipolytica species.

Impact of air-polishing using erythritol on surface roughness and substance loss in dental hard tissue: An ex vivo study.

This ex vivo study aimed to investigate surface roughness and substance loss after treatment with different professional cleaning methods and to determine whether subsequent polishing with a rubber cup and polishing paste is necessary. Samples (flat and natural surfaces) of human enamel and dentin were prepared (baseline) and treated with either a curette, air-polishing with erythritol, a rubber cup and polishing paste, or a combination thereof (treatment). Subsequently, all samples were immersed in an ultrasonic bath (ultrasonic) to remove residues from the treatment procedures. The surface roughness values sRa and sRz as well as tissue loss were measured profilometrically. Linear regression models were used to compare group differences (roughness and loss) considering the corresponding baseline value. The significance level was set at p<0.05. sRa increased significantly after treatment with curettes or air-polishing with erythritol in both enamel (p<0.001) and dentin (p<0.001) of flat samples. The same effect was observed for sRz in dentin (p<0.001) but not for enamel compared to negative control. Polishing with a rubber cup and paste alone had no significant effect on roughness values. When combined with other treatments, the effect of curette or air-polishing with erythritol dominated the effect. In enamel, none of the tested methods led to measurable tissue loss. In dentin, air-polishing with erythritol caused ≤50% tissue loss compared to the curette. Conclusively, for enamel, treatment effects on roughness were measurable but of limited clinical relevance. For dentin, air-polishing resulted in a smaller but insignificant roughness increase and less tissue loss compared to the curette. Polishing with a rubber cup and paste did not affect surface roughness. Regarding the clinical application, the use of air-polishing seems to be a less invasive procedure than using a curette; polishing with rubber cup and paste offers no advantage in terms of reducing roughness as a final procedure.

Air powder waterjet technology using erythritol or glycine powders in periodontal or peri-implant prophylaxis and therapy: A consensus report of an expert meeting.

OBJECTIVES: To attain a collective expert opinion on the use of air powder waterjet technology (APWT) with erythritol and glycine powders in the prophylaxis and therapy of periodontal and peri-implant diseases. MATERIAL AND METHODS: In the first step, a modified one-round online Delphi survey including 44 five-point Likert scale questions was conducted among a group of 10 expert clinicians and researchers with thorough knowledge and experience in this topic. In the second step, the single questions and the survey results were discussed during a meeting, and consensus statements were formulated, respectively. RESULTS: An agreement was reached on most items, especially opinions supporting glycine and erythritol powders as favorable with respect to efficiency, safety, and comfort. More scientific evidence is needed to support the improvement in clinical attachment on teeth and implants, especially when APWT with erythritol is used. In addition, APWT needs more long-term evaluation and studies in terms of microbiome/microbiological effects as well as effects on the inflammatory response on natural teeth and implants, also in light of a guided biofilm therapy concept. CONCLUSIONS: In line with the expert opinions and supported by the evidence, it was concluded that the use of APWT with erythritol and glycine powders in nonsurgical periodontal and peri-implant therapy and prophylaxis is patient compliant and efficient.

Effects of nonnutritive sugar inclusion in laboratory diets and attracticidal spheres on survivorship and mobility of 2 Dipteran species, Rhagoletis pomonella (Diptera: Tephritidae) and Drosophila suzukii (Diptera: Drosophilidae).

Native apple maggot fly, Rhagoletis pomonella, and invasive spotted-wing drosophila, Drosophila suzukii, are key pests of apple and small fruit, respectively, in the United States. Both species are typically managed with standard insecticide applications. However, interest in alternative strategies that result in insecticide reductions has led to evaluations of nonnutritive sugars as toxicants for Drosophila species and development of attracticidal spheres for both species. Here, we evaluated the survivorship of R. pomonella and D. suzukii when provided with standard diets that substituted saccharin, sucralose, aspartame, erythritol, dextrose, or mannitol for the sucrose component and compared them with standard diets and water-only controls for up to 15 days. Presence of erythritol and mannitol significantly decreased survivorship of R. pomonella and erythritol significantly decreased the survivorship of D. suzukii. However, mobility trials following a 2 h exposure to aqueous solutions of each sugar treatment resulted in no strong impact on either species. Survivorship after 30 min exposure to erythritol or mannitol alone, or in combination with varying concentrations of sucrose (serving as a phagostimulant) at 30 min and 24 h were evaluated for both species. Only D. suzukii survivorship was affected with decreased survivorship on erythritol:sucrose solutions of 20:0% and 15:5% for 24 h. Based on all results, erythritol appeared most promising, and was integrated into attracticidal spheres as a toxicant but even at the highest concentration, survivorship remained unaffected for either species, thus making this nonnutritive sugar impractical and ineffective as a toxicant substitute in attracticidal spheres.

Cloning and Functional Characterization of 2-C-methyl-D-erythritol-4-phosphate cytidylyltransferase (LiMCT) Gene in Oriental Lily (Lilium 'Sorbonne').

2-C-methyl-D-erythritol-phosphate cytidylyltransferase (MCT) is a key enzyme in the MEP pathway of monoterpene synthesis, catalyzing the generation of 4- (5'-pyrophosphate cytidine)-2-C-methyl-D-erythritol from 2-C-methyl-D-erythritol-4-phosphate. We used homologous cloning strategy to clone gene, LiMCT, in the MEP pathway that may be involved in the regulation of floral fragrance synthesis in the Lilium oriental hybrid 'Sorbonne.' The full-length ORF sequence was 837 bp, encoding 278 amino acids. Bioinformatics analysis showed that the relative molecular weight of LiMCT protein is 68.56 kD and the isoelectric point (pI) is 5.12. The expression pattern of LiMCT gene was found to be consistent with the accumulation sites and emission patterns of floral fragrance monoterpenes in transcriptome data (unpublished). Subcellular localization indicated that the LiMCT protein is located in chloroplasts, which is consistent with the location of MEP pathway genes functioning in plastids to produce isoprene precursors. Overexpression of LiMCT in Arabidopsis thaliana affected the expression levels of MEP and MVA pathway genes, suggesting that overexpression of the LiMCT in A. thaliana affected the metabolic flow of C5 precursors of two different terpene synthesis pathways. The expression of the monoterpene synthase AtTPS14 was elevated nearly fourfold in transgenic A. thaliana compared with the control, and the levels of carotenoids and chlorophylls, the end products of the MEP pathway, were significantly increased in the leaves at full bloom, indicating that LiMCT plays an important role in regulating monoterpene synthesis and in the synthesis of other isoprene-like precursors in transgenic A. thaliana flowers. However, the specific mechanism of LiMCT in promoting the accumulation of isoprene products of the MEP pathway and the biosynthesis of floral monoterpene volatile components needs further investigation.

Simultaneous analysis of natural and artificial sweeteners in sugar-free drinks and urine samples by column-switching UHPLC-charged aerosol detection method.

Sweeteners are considered an alternative to high-calorie foods or drinks and have been widely used globally. However, the simultaneous separation and detection of high-polarity natural and artificial sweeteners are challenging owing to their broad-spectrum physical and chemical properties. Herein, we developed a column-switching UHPLCCAD method and used it for detecting and quantitating 12 sweeteners, including natural sweeteners (erythritol, mannitol, xylitol, sorbitol and stevioside) and artificial sweeteners (acesulfame potassium, saccharin sodium salt, sodium cyclamate, sucralose, aspartame, alitame and neotame). The LOD and LOQ were 0.932-6.25 µg/mL and 3.10-20.83 µg/mL, respectively, and the method demonstrated excellent linearity (R² ≥ 0.9990), good precision (intraday and interday precision was 0.59-6.88 %), and high recovery (average recoveries were 85.16-108.64 %). This method was applied to determine the sweeteners in 15 sugar-free drinks purchased from the local Chinese supermarkets. What's more, natural sweetener erythritol and artificial sweetener acesulfame potassium were suspected over addition in sugar-free drinks. Meanwhile the method was applied to the sweeteners in various sugar-free drinks and the dynamic monitoring of transit and excretion in vivo after drinking. Those prove that the method can be used to the detection of sugar free drinks and quality control of the sweeteners. The study highlights the potential of UHPLC-charged aerosol detection technology in detection of multiple components in food industry.

Ice cream with sucralose, stevioside, and erythritol as sugar substitutes: Sensory profile and customer preference.

Sugar-free food has been gaining popularity because of low-calorie content. But sugar replacement by high-intensity sweeteners can negatively affect sensory. In this study, the effect of the addition of sucralose (Suc), stevioside (Ste), and erythritol (Ery) as sugar substitutes on the sensory profile and overall acceptance of ice cream were evaluated by penalty analysis (PA) based on the check-all-that apply (CATA) method, with those of the partial least squares (PLS) regression. Twelve sweetening agents of ice cream samples were presented to 106 consumers who answered on an overall liking question using the 15-point hedonic scale and a CATA question with 32 attributes that described the sensory characteristics of ice cream. The results showed that mixed sweeteners (60%Suc+20%Ste+20%Ery or 60%Suc+10%Ste+30%Ery) can present an advantageous performance when used separately, and making ice cream similar to that of sucrose (Sac) added. Adding Suc, Ste, and Ery to ice cream hardly felt bitterness, astringency, and chemical-like sensations of the sweetening agent. The significant difference between different sweeteners is the intensity and speed of sweetness. Developing combination of high-potency sweeteners that can make sweetness appear quickly could open up new ways to design sugar-free ice cream.

Design and synthesis of fosmidomycin analogs containing aza-linkers and their biological activity evaluation.

BACKGROUND: The enzymes involved in the 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway are attractive targets of a new mode of action for developing anti-infective drugs and herbicides, and inhibitors against 1-deoxy-d-xylulose 5-phosphate reductoisomerase (IspC), the second key enzyme in the pathway, have been intensively investigated; however, few works are reported regarding IspC inhibitors designed for new herbicide discovery. RESULTS: A series of fosmidomycin (FOS) analogs were designed with nitrogen-containing linkers replacing the trimethylene linker between the two active substructures of FOS, phosphonic acid and hydroxamic acid. Synthesis followed a facile three-step route of sequential aza-Michael addition of α-amino acids to dibenzyl vinylphosphonate, amidation of the amino acid carboxyl with O-benzyl hydroxylamine, and simultaneous removal of the benzyl protective groups. Biological activity evaluation of IspC and model plants revealed that some compounds had moderate enzyme and model plant growth inhibition effects. In particular, compound 10g, which has a N-(4-fluorophenylethyl) nitrogen-containing linker, exhibited the best plant inhibition activities, superior to the control FOS against the model plants Arabidopsis thaliana, Brassica napus L., Amaranthus retroflexus and Echinochloa crus-galli. A dimethylallyl pyrophosphate rescue assay on A. thaliana confirmed that both 10g and FOS exert their herbicidal activity by blocking the MEP pathway. This result consistent with molecular docking, which confirmed 10g and FOS binding to the IspC active site in a similar way. CONCLUSION: Compound 10g has excellent herbicidal activity and represents the first herbicide lead structure of a new mode of action that targets IspC enzyme in the MEP pathway. © 2023 Society of Chemical Industry.

Insight into the effect of osmosis agents on macro- and micro- texture, water distribution, and thermal stability of instant controlled pressure drop drying peach chips.

To investigate the influence of sugar structure on the quality of peach chips produced using osmotic dehydration (OD) in combination with instant controlled pressure drop (DIC) drying, erythritol, glucose, maltose, and trehalose were selected as osmotic agents. The properties of the osmotic solutions, as well as the macro- and micro-texture, water distribution, and thermal stability of peach chips were investigated. Results showed that OD pretreatments inhibited the formation of large cavity structures. The highest hardness (101.34 N) and the lowest hydrophobicity (0°) were obtained in erythritol-OD samples. Trehalose-OD samples with the most homogeneous pore structure exhibited the highest crispness (1.05 mm) and the highest glass transition temperature (52.06 °C). Various absorption peaks of peach chips pretreated with different OD methods, characterized by Raman spectroscopy, suggested changes in composition and functional groups due to the diffusion of sugars into the cells of peach tissues, which also contributed to the higher Tg.

Carbohydrate-Templated Syntheses of Trifluoromethyl-Substituted MEP Analogues for the Study of the Methylerythritol Phosphate Pathway.

Trifluoromethyl analogues of methylerythritol phosphate (MEP) and 2-C-methyl-erythritol 2,4-cyclodiphosphate (MEcPP), natural substrates of key enzymes from the MEP pathway, were prepared starting from d-glucose as the chiral template to secure absolute configurations. The obligate trifluoromethyl group was inserted with complete diastereoselectivity using the Ruppert-Prakash nucleophile. Target compounds were assayed against the corresponding enzymes showing that trifluoro-MEP did not disrupt IspD activity, whereas trifluoro-MEcPP induced 40% inhibition of IspG at 1 mM.

Mechanism and evolutionary analysis of Yarrowia lipolytica CA20 capable of producing erythritol with a high yield based on comparative genomics.

Combined mutagenesis is widely applied for the breeding of robust Yarrowia lipolytica used in the production of erythritol. However, the changes of genome after mutagenesis remains unclear. This study aimed to unravel the mechanism involved in the improved erythritol synthesis of CA20 and the evolutionary relationship between different Y. lipolytica by comparative genomics analysis. The results showed that the genome size of Y. lipolytica CA20 was 20,420,510 bp, with a GC content of 48.97%. There were 6330 CDS and 649 ncRNA (non-coding RNA) in CA20 genome. Average nucleotide identity (ANI) analysis showed that CA20 genome possessed high similarity (ANI > 99.50%) with other Y. lipolytica strains, while phylogenetic analysis displayed that CA20 was classified together with Y. lipolytica IBT 446 and Y. lipolytica H222. CA20 shared 5342 core orthologous genes with the 8 strains while harbored 65 specific genes that mainly participated in the substrate and protein transport processes. CA20 contained 166 genes coding for carbohydrate-active enzymes (CAZymes), which was more than that found in other strains (108－137). Notably, 4, 2, and 13 different enzymes belonging to glycoside hydrolases (GHs), glycosyltransferases (GTs), and carbohydrate esterases (CEs), respectively, were only found in CA20. The enzymes involved in the metabolic pathway of erythritol were highly conserved in Y. lipolytica, except for transaldolase (TAL1). In addition, the titer and productivity of erythritol by CA20 were 190.97 g/L and 1.33 g/L/h, respectively, which were significantly higher than that of WT5 wherein 128.61 g/L and 0.92 g/L/h were obtained (P< 0.001). Five frameshift mutation genes and 15 genes harboring nonsynonymous mutation were found in CA20 compared with that of WT5. Most of these genes were involved in the cell division, cell wall synthesis, protein synthesis, and protein homeostasis maintenance. These findings suggested that the genome of Y. lipolytica is conserved during evolution, and the variance of living environment is one important factor leading to genome divergence. The varied number of CAZymes existed in Y. lipolytica is one factor that contributes to the performance difference. The increased synthesis of erythritol by Y. lipolytica CA20 is correlated with the improvement of the stability of cell structure and internal environment. The results of this study provide a basis for the directional breeding of robust strains used in erythritol production.

Construction of a xylose metabolic pathway in Trichosporonoides oedocephalis ATCC 16958 for the production of erythritol and xylitol.

PURPOSE: Erythritol is a valuable compound as sweetener and chemical material however cannot be fermented from the abundant substrate xylose. METHODS: The strain Trichosporonoides oedocephalis ATCC 16958 was employed to produce polyols including xylitol and erythritol by metabolic engineering approaches. RESULTS: The introduction of a substrate-specific ribose-5-phosphate isomerase endowed T. oedocephalis with xylose-assimilation activity to produce xylitol, and eliminated glycerol production simultaneously. A more value-added product, erythritol was produced by further introducing a homologous xylulose kinase. The carbon flux was redirected from xylitol to erythritol by adding high osmotic pressure. The production of erythritol was improved to 46.5 g/L in flasks by fermentation adjustment, and the process was scaled up in a 5-L fermentor, with a 40 g/L erythritol production after 120 h, and a time-space yield of 0.56 g/L/h. CONCLUSION: This study demonstrated the potential of T. oedocephalis in the synthesis of multiple useful products from xylose.