Palmitoleic acid-rich oleaginous yeast Scheffersomyces segobiensis DSM 27193 exerts anti-obesity effects by ameliorating hepatic steatosis and adipose tissue hypertrophy.

BACKGROUND: Yeast biomass, encompassing fatty acids, terpenoids, vitamins, antioxidants, enzymes, and other bioactive compounds have been extensively utilized in food-related fields. The safety and potential bioactivities of Scheffersomyces segobiensis DSM 27193, an oleaginous yeast strain, are unclear. RESULTS: Scheffersomyces segobiensis DSM 27193 accumulated large palmitoleic acid (POA) levels (43.4 g kg-1 biomass) according to the results of whole-cell components. We annotated the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, and predicted the categories and host of the pathogen-host interactions (PHI) genes in S. segobiensis DSM 27193. However, S. segobiensis DSM 27193 did not exert toxic effects in mice. Administration of S. segobiensis DSM 27193 led to substantial weight reduction by diminishing food intake in an obesity mouse model. Additionally, it reversed hepatic steatosis and adipose tissue hypertrophy, and improved abnormalities in serum biochemical profiles such as triglyceride, total cholesterol, low-density lipoprotein cholesterol, lipopolysaccharide, tumor necrosis factor-α, interleukin-1ß, and interleukin-6. CONCLUSION: This study is the first to illustrate the safety and effects of S. segobiensis DSM 27193 against obesity and offers a scientific rationale for its application in functional food supplements. © 2023 Society of Chemical Industry.

Genome Characterization of Pseudomonas aeruginosa KT1115, a High Di-rhamnolipid-Producing Strain with Strong Oils Metabolizing Ability.

In this study, a wild-type Pseudomonas aeruginosa strain KT1115 with the capability of converting rapeseed oils into di-rhamnolipids, a class of biosurfactants with extensive application potential, was successfully isolated and characterized. Di-rhamnolipids production by microorganism culture provided a mild, eco-friendly, and secure approach for surfactants production instead of conventional chemical synthesis. However, few studies have been attempted to explore the metabolic mechanism behind the high di-rhamnolipids production by P. aeruginosa. Here, we presented the graft genome of a wild-type P. aeruginosa strain KT1115, with emphasis on the analysis of oils metabolism and rhamnolipid synthesis. The availability of the genome sequence provides additional insight into the genetic mechanism enhancing di-rhamnolipids biosynthesis.

Current status and perspectives of 2-phenylethanol production through biological processes.

2-Phenylethanol (2-PE), an important flavor and fragrance compound with a rose-like smell has been widely used in the cosmetics, perfume, and food industries. Traditional production of 2-PE was mainly through the extraction from plant materials or by chemical synthesis. However, the increasing demand of consumers for natural flavors cannot be met by these methods. Biological production of 2-PE has emerged to be an appealing solution due to an environmental friendly process and the definition of a "natural" product. In this review, we have comprehensively summarized the current status and perspectives for biological 2-PE production in terms of its advantages over classical chemical synthesis and extraction from natural plants. A comprehensive description of 2-PE synthetic pathways and global regulation mechanisms, strategies to increase 2-PE production, and the utilization of agro-industrial wastes as feedstocks has been systematically discussed. Furthermore, the application of in situ product removal techniques have also been highlighted.

Facile synthesis of NiFe2O4-based nanoblocks for low-temperature detection of trace n-butanol.

Fe2O3-loaded NiFe2O4 nanoblocks were successfully developed under a straightforward one-step hydrothermal synthesis method, aiming to detect trace amounts of n-butanol at the parts per billion (ppb) concentration range. The synthesized samples were comprehensively characterized using various techniques, including XRD, SEM, XPS, TEM and SAED. At a tantalizingly low temperature of 130 °C, the Ni/Fe-2 gas sensor demonstrated the optimum response (Ra/Rg = 29.747 @ 10 ppm) to n-butanol. Furthermore, Ni/Fe-2 sensor exhibited remarkable stability and reproducibility and an ultra-low detection limit. The enhanced gas sensitivity was primarily due to the assembly of Ni/Fe-2 nanoblocks from differently sized nanospheres, which exhibited a rich surface porosity conducive to gas adsorption. Besides, the formation of heterojunctions and the augmentation of oxygen vacancy content are also conducive to enhancing gas sensing capabilities. The Ni/Fe-2 sensor is expected to successfully detect trace amounts of n-butanol.

Anti-aging effect of glycerophosphocholine in Steinernema kraussei 0657L.

Glycerophosphocholine (GPC) is a water-soluble small molecule found naturally in humans and foods such as milk and soybeans. It can activate the IIS pathway by regulating the expression of daf-2, ins-18 and daf-16 genes, sek-1 and skn-1 genes of MAPK pathway, sod-3, ctl-1, gst-4 and other antioxidant genes. GPC can relieve symptoms related to aging in organisms. The aim of this study was to probe the effects of GPC on the longevity and stress resistance of the entomopathogenic nematode (EPN) Steinernema kraussei 0657L strain. The results showed that the lifespan of S. kraussei 0657L was significantly prolonged by 50 mM GPC treatment, which was 54.55% longer than that of the control (0 mM GPC). GPC significantly inhibited reactive oxygen species (ROS) and lipofuscin accumulation, but the body size and fecundity of S. kraussei 0657L had little changed. At the same time, the longevity of S. kraussei 0657L exposed to heat shock and UV-B radiation was significantly prolonged than that with no external stress. GPC supplementation increased the activity of antioxidant enzymes and corresponding gene expression. Under treatment with 50 mM GPC, the activities of superoxide dismutase and catalase were increased by 1.90- and 4.13-fold, respectively, the expression of the sod-3 and ctl-1 genes was increased by 3.60- and 0.60-fold, respectively, and harmful reactive oxygen species were removed. In addition, the expression levels of the ins-18, skn-1, sek-1 and gst-4 genes related to the insulin/IGF-1 signaling pathway were upregulated 1.04-, 1.84-, 2.21- and 1.24-fold, respectively. These results indicate that GPC is mainly involved in the lifespan regulation of S. kraussei 0657L and plays an important role in resistance to external stress by activating the insulin/IGF-1 signaling pathway and downstream PI3K/MAPK kinase, creating a new idea for improving the commercial efficacy of S. kraussei. It also laid a theoretical foundation for its further efficient development and utilization in the field of biological control.

Engineering Scheffersomyces segobiensis for palmitoleic acid-rich lipid production.

Palmitoleic acid (POA; C16:1) is an essential high-value ω-7-conjugated fatty acid with beneficial bioactivities and potential applications in the nutraceutical and pharmaceutical industries. Previously, the oleaginous yeast Scheffersomyces segobiensis DSM27193 has been identified as a promising production host as an alternative for POA extraction from plant or animal sources. Here, the POA-producing capacity of this host was further expanded by optimizing the fermentation process and molecular strain engineering. Specifically, a dual fermentation strategy (O-S dynamic regulation strategy) focused on the substrate and dissolved oxygen concentration was designed to eliminate ethanol and pyruvate accumulation during fermentation. Key genes influencing POA production, such as jen, dgat, ole were identified on the transcriptional level and were subsequently over-expressed. Furthermore, the phosphoketolase (Xpk)/phosphotransacetylase (Pta) pathway was introduced to improve the yield of the precursor acetyl-CoA from glucose. The resulting cell factory SS-12 produced 7.3 g/L of POA, corresponding to an 11-fold increase compared to the wild type, presenting the highest POA titre reported using oleaginous yeast to date. An economic evaluation based on the raw materials, utilities and facility-dependent costs showed that microbial POA production using S. segobiensis can supersede the current extraction method from plant oil and marine fish. This study reports the construction of a promising cell factory and an effective microbial fermentation strategy for commercial POA production.

Tandem chemical deconstruction and biological upcycling of poly(ethylene terephthalate).

Upcycling processes via tandem chemical deconstruction and biological transformation has shown promise for poly(ethylene terephthalate) (PET) waste open-loop management. Under this framework, postconsumer PET becomes a low-cost and abundant starting material for the synthesis of high-value chemicals.

Integration of ARTP Mutation and Adaptive Laboratory Evolution to Reveal 1,4-Butanediol Degradation in Pseudomonas putida KT2440.

Biotransformation of plastics or their depolymerization monomers as raw materials would offer a better end-of-life solutions to the plastic waste dilemma. 1,4-butanediol (BDO) is one of the major depolymerization monomers of many plastics polymers. BDO valorization presents great significance for waste plastic up-recycling and fermenting feedstock exploitation. In the present study, atmospheric pressure room temperature plasma (ARTP)-induced mutation combined with adaptive laboratory evolution (ALE) was used to improve the BDO utilization capability of Pseudomonas putida KT2440. The excellent mutant P. putida NB10 was isolated and stored in the China Typical Culture Preservation Center (CCTCC) with the deposit number M 2021482. Whole-genome resequencing and transcriptome analysis revealed that the BDO degradation process consists of ß-oxidation, glyoxylate carboligase (GCL) pathway, glyoxylate cycle and gluconeogenesis pathway. The imbalance between the two key intermediates (acetyl-CoA and glycolyl-CoA) and the accumulation of cytotoxic aldehydes resulted in the weak metabolism performance of KT2440 in the utilization of BDO. The balance of the carbon flux and enhanced tolerance to cytotoxic intermediates endow NB10 with great BDO degradation capability. This study deeply revealed the metabolic mechanism behind BDO degradation and provided an excellent chassis cell for BDO further up-cycling to high-value chemicals. IMPORTANCE Plastic waste represents not only a global pollution problem but also a carbon-rich, low-cost, globally renewable feedstock for industrial biotechnology. BDO is the basic material for polybutylene terephthalate (PBT), poly butylene adipate-co-terephthalate (PBAT), poly (butylene succinate) (PBS), etc. Herein, the construction of BDO valorization cell factory presents great significance for waste plastic up-recycling and novel fermentation feedstock exploitation. However, BDO is hard to be metabolized and its metabolic pathway is unclear. This study presents a P. putida mutant NB10, obtained through the integration of ARTP and ALE, displaying significant growth improvement with BDO as the sole carbon source. Further genome resequencing, transcriptome analysis and genetic engineering deeply revealed the metabolic mechanism behind BDO degradation in P. putida, this study offers an excellent microbial chassis and modification strategy for plastic waste up-cycling.

Bioengineering Comamonas testosteroni CNB-1: a robust whole-cell biocatalyst for efficient PET microplastic degradation.

The escalating crisis of polyethylene terephthalate (PET) microplastic contamination in biological wastewater treatment systems is a pressing environmental concern. These microplastics inevitably accumulate in sewage sludge due to the absence of effective removal technologies. Addressing this urgent issue, this study introduces a novel approach using DuraPETase, a potent enzyme with enhanced PET hydrolytic activity at ambient temperatures. Remarkably, this enzyme was successfully secreted from Comamonas testosteroni CNB-1, a dominant species in the active sludge. The secreted DuraPETase showed significant hydrolytic activity toward p-NPB and PET nanoplastics. Furthermore, the CNB-1 derived whole-cell biocatalyst was able to depolymerize PET microplastics under ambient temperature, achieving a degradation efficiency of 9% within 7 days. The CNB-1-based whole biocatalysts were also capable of utilizing PET degradation intermediates, such as terephthalic acid (TPA) and ethylene glycol (EG), and bis(2-hydroxyethyl)-TPA (BHET), for growth. This indicates that it can completely mineralize PET, as opposed to merely breaking it down into smaller molecules. This research highlights the potential of activated sludge as a potent source for insitu microplastic removal.

Characterization of polyhydroxybutyrate (PHB) synthesized by newly isolated rare actinomycetes Aquabacterium sp. A7-Y.

Polyhydroxyalkanoates (PHAs) as biodegradable plastics have attracted increasing attention due to its biodegradable, biocompatible and renewable advantages. Exploitation some unique microbes for PHAs production is one of the most competitive approaches to meet complex industrial demand, and further develop next-generation industrial biotechnology. In this study, a rare actinomycetes strain A7-Y was isolated and identified from soil as the first PHAs producer of Aquabacterium genus. Produced PHAs by strain A7-Y was identified as poly(3-hydroxybutyrate) (PHB) based on its structure characteristics, which is also similar with commercial PHB. After optimization of fermentation conditions, strain A7-Y can produce 10.2 g/L of PHB in 5 L fed-batch fermenter, corresponding with 54 % PHB content of dry cell weight, which is superior to the reported actinomycetes species. Furthermore, the phaCAB operon in stain A7-Y was excavated to be responsible for the efficient PHB production and verified in recombinant Escherichia coli. Our results indicate that strain A7-Y and its biosynthetic gene cluster are potential candidates for developing a microbial formulation for the PHB production.

High-yield and nitrogen self-doped hierarchical porous carbon from polyurethane foam for high-performance supercapacitors.

Confronted with the environmental pollution and energy crisis issues, upcycling of waste plastics for energy-storage applications has attracted broad interest. Polyurethane (PUR) is a potential candidate for the preparation of N-doped carbon materials. However, its low carbon yield limits the utilization of PUR waste. In this study, PUR foam was converted into N-doped hierarchical porous carbon (NHPC) through an autogenic atmosphere pyrolysis (AAP)-KOH activation approach. An ultra-high carbon yield of 55.0% was achieved through AAP, which is more than 17 times the carbon yield of conventional pyrolysis of PUR. AAP converted 83.2% of C and 61.0% of N in PUR into derived carbon material. The high conversion rate and self-doping effect can increase the environmental and economic benefits of this approach. KOH activation significantly increased the specific surface area of carbon materials to 2057 m2 g-1 and incorporated hierarchical porous structure and O-containing functional groups to the carbon materials. The obtained NHPCs were applied to improve the performance of supercapacitors. The electrochemical measurement revealed that NHPCs exhibited a high specific capacitance of 342 F g-1 (133 F cm-3) at 0.5 A g-1, low resistance, and outstanding cycling stability. The energy density and power density of the supercapacitor were improved to 11.3 W h kg-1 and 250 W kg-1, respectively. This research developed a possible solution to plastic pollution and energy shortage.

Transcription-Associated Fluorescence-Activated Droplet Sorting for Di-rhamnolipid Hyperproducers.

Rhamnolipids (RLs) are biosurfactants with great economic significance that have been used extensively in multiple industries. Pseudomonas aeruginosa is a promising microorganism for sustainable RL production. However, current CTAB-MB based screening of RL-producing strains is time-consuming, labor-intensive, and unable to distinguish mono- and di-RL. In this study, we developed a novel transcription-associated fluorescence-activated droplet sorting (FADS) method to specifically target the di-RL hyperproducers. We first investigated critical factors associated with this method, including the specificity and sensitivity for discriminating di-RL overproducers from other communities. Validation of genotype-phenotype linkage between the GFP intensity, rhlC transcription, and di-RL production showed that rhlC transcription is closely correlated with di-RL production, and the GFP intensity is responsive to rhlC transcription, respectively. Using this platform, we screened out ten higher di-RL producing microorganisms, which produced 54-208% more di-RL than the model P. aeruginosa PAO1. In summary, the droplet-based microfluidic platform not only facilitates a more specific, reliable, and rapid screening of P. aeruginosa colonies with desired phenotypes, but also shows that intracellular transcription-associated GFP intensity can be used to measure the yield of di-RL between populations of droplets containing different environmental colonies. This method also can be integrated with transposon mutation libraries to target P. aeruginosa mutants.

Construction and comparison of synthetic microbial consortium system (SMCs) by non-living or living materials immobilization and application in acetochlor degradation.

The microbial degradation of pesticides by pure or mixed microbial cultures has been thoroughly explored, however, they are still difficult to apply in real environmental remediation. Here, we constructed a synthetic microbial consortium system (SMCs) through the immobilization technology by non-living or living materials to improve the acetochlor degradation efficiency. Rhodococcus sp. T3-1, Delftia sp. T3-6 and Sphingobium sp. MEA3-1 were isolated for the SMCs construction. The free-floating consortium with the composition ratio of 1:2:2 (Rhodococcus sp. T3-1, Delftia sp. T3-6 and Sphingobium sp. MEA3-1) demonstrated 94.8% degradation of acetochlor, and the accumulation of intermediate metabolite 2-methyl-6-ethylaniline was decreased by 3 times. The immobilized consortium using composite materials showed synergistic effects on the acetochlor degradation with maximum degradation efficiency of 97.81%. In addition, a novel immobilization method with the biofilm of Myxococcus xanthus DK1622 as living materials was proposed. The maximum 96.62% degradation was obtained in non-trophic media. Furthermore, the immobilized SMCs showed significantly enhanced environmental robustness, reusability and stability. The results indicate the promising application of the immobilization methods using composite and living materials in pollutant-contaminated environments.

Increased Lipid Production in Yarrowia lipolytica from Acetate through Metabolic Engineering and Cosubstrate Fermentation.

Bioconversion of acetate, a byproduct generated in industrial processes, into microbial lipids using oleaginous yeasts offers a promising alternative for the economic utilization of acetate-containing waste streams. However, high acetate concentrations will inhibit microbial growth and metabolism. In this study, the acetate utilization capability of Yarrowia lipolytica PO1f was successively improved by overexpressing the key enzyme of acetyl-CoA synthetase (ACS), which resulted in an accumulation of 9.2% microbial lipids from acetate in shake flask fermentation. By further overexpressing the second key enzymes of acetyl-CoA carboxylase (ACC1) and fatty acid synthase (FAS) in Y. lipolytica, the lipid content was increased to 25.7% from acetate. Finally, the maximum OD600 of 29.2 and a lipid content of 41.7% were obtained with the engineered strain by the adoption of cosubstrate (glycerol and acetate) fed-batch fermentation, which corresponded to an increase of 68 and 95%, respectively. These results presented a promising strategy for economic and efficient microbial lipid production from the waste acetate.

The draft genome sequence of Scheffersomyces segobiensis strain DSM 27193, a yeast capable of producing palmitoleic acid-rich lipids.

In this study, the draft genome of the recently isolated oleaginous yeast Scheffersomyces segobiensis DSM 27193, which can accumulate high content of palmitoleic acid (POA), was sequenced and analyzed. Only few studies have reported about POA-rich lipid production by Scheffersomyces segobiensis so far. The ITS region analysis indicated that strain DSM 27193 is closely related to Pichia segobiensis and Scheffersomyces stipitis. The size of the assembled draft genome of strain DSM 27193 is 14.8 Mb, containing 5477 encoded protein sequences with a G + C content of 40.83%. Among the annotated genes, two stearoyl-CoA desaturases encoded by ole1 and ole2 were identified which are potentially involved in POA accumulation. Further analysis of POA-rich lipid synthesis pathway genes in S. segobiensis DSM 27193 will provide additional insights for POA artificial synthesis through metabolic engineering.

Biotechnological applications of the non-conventional yeast Meyerozyma guilliermondii.

Unconventional yeasts have attracted increased attentions owning to their unique biochemical properties and potential application in the biotechnological process. With the rapid development of microbial isolation tools and synthetic biology, more promising industrial yeasts have been isolated and characterized. Meyerozyma guilliermondii (anamorph Candida guilliermondii) is an ascomycetous yeast with several unique characteristics and physiology, such as the wide substrates spectrum and capability of various chemicals synthesis. The potential physiological and metabolic capabilities of M. guilliermondii, which can utilize various carbon sources including typical hydrophilic and hydrophobic materials were first reviewed in this review. Moreover, the wide applications of M. guilliermondii, such as for industrial enzymes production, metabolites synthesis and biocontrol were also reviewed. With the development of system and synthetic biology, M. guilliermondii will provide new opportunities for potential applications in biotechnology sectors in the future.

Biodegradation and up-cycling of polyurethanes: Progress, challenges, and prospects.

Polyurethanes (PUR) are ranked globally as the 6th most abundant synthetic polymer material. Most PUR materials are specifically designed to ensure long-term durability and high resistance to environmental factors. As the demand for diverse PUR materials is increasing annually in many industrial sectors, a large amount of PUR waste is also being generated, which requires proper disposal. In contrast to other mass-produced plastics such as PE, PP, and PET, PUR is a family of synthetic polymers, which differ considerably in their physical properties due to different building blocks (for example, polyester- or polyether-polyol) used in the synthesis. Despite its xenobiotic properties, PUR has been found to be susceptible to biodegradation by different microorganisms, albeit at very low rate under environmental and laboratory conditions. Discovery and characterization of highly efficient PUR-degrading microbes and enzymes capable of disassembling PUR polymer chains into oligo- and monomeric compounds is of fundamental importance for a circular plastic economy. In this review, the main methods used for screening PUR-degrading microbes and enzymes are summarized and compared in terms of their catalytic mechanisms. Furthermore, recycling and upcycling strategies of waste PUR polymers, including microbial conversion of PUR monomers into value added products, are presented.

[Efficacy and safety of tranexamic acid in total hip arthroplasty via direct anterior approach].

OBJECTIVE: To evaluate the efficacy and safety of local application of tranexamic acid (TXA) in reducing perioperative blood loss in total hip arthroplasty via direct anterior approach (DAA). METHODS: From July 2013 to September 2018, 46 patients with avascular necrosis of the femoral head were divided into tranexamic acid group (n=23) and saline group (n=23). In the tranexamic acid group, there were 14 males and 9 females, aged 52 to 72(63.70±5.34) years old. They were diluted with 3 g tranexamic acid in 50 ml normal saline and immersed in the joint cavity for 3 min after prosthesis replacement;in the normal saline group, there were 13 males and 10 females, aged 55 to 73 (61.26±5.78) years, who were treated with the sameamount of normal saline. The blood loss, hemoglobin value, number of blood transfusion cases, the time of first landing after operation, the incidence of thrombosis and incision adverse events were compared between the two groups. Harris score was used to evaluate hip joint function at 1 and 3 months after operation. RESULTS: The incision healed well and no obvious complications occurred in the two groups. All patients were followed up for 12 to 59 months(averaged 31.11 months). No hip pain was found in the follow-up patients. Hip joint function was improved effectively and no prosthesis loosening occurred. The total perioperative blood loss in tranexamic acid group and normal saline group was(740.09±77.14) ml and (1 069.07±113.53) ml respectively, 24 hours after operation, the drainage volume was (87.61±9.28) ml, (233.83±25.62) ml, the hidden blood loss was (409.65±38.01) ml and (588.33±57.16) ml. the difference of hemoglobin before and after operation was (24.78±2.19) g / L and (33.57±2.95) g / L, the difference was statistically significant (P<0.05). There was no significant difference in blood loss, incidence of deep vein thrombosis and pulmonary embolism, and Harris score of hip joint between the two groups (P>0.05). CONCLUSION: local application of tranexamic acid in total hip arthroplasty through direct anterior approach can safely and effectively reduce perioperative blood loss, and does not increase the risk of thrombosis, and does not affect the normal recovery of joint function.

Biotechnological potential and applications of microbial consortia.

Recent advances in microbial consortia present a valuable approach for expanding the scope of metabolic engineering. Systems biology enable thorough understanding of diverse physiological processes of cells and their interactions, which in turn offers insights into the optimal design of synthetic microbial consortia. Yet, the study of synthetic microbial consortia is still in early infancy, facing many unknowns and challenges in intercellular communication and construction of stable and controllable microbial consortia systems. In this review, we comprehensively discussed the recent application of defined microbial consortia in the fields of human health monitoring and medicine exploitation, valuable compounds synthesis, consolidated bioprocessing of lignocellulosic materials and environmental bioremediation. Moreover, the outstanding challenges and future directions to advance the development of high-efficient, stable and controllable synthetic microbial consortia were highlighted.

Comprehensive investigations of 2-phenylethanol production by high 2-phenylethanol tolerating Meyerozyma sp. strain YLG18.

2-Phenylethanol (2-PE) production through bio-synthesis method has become an appealing option owning to the mild conditions and high product selectivity. However, 2-PE is toxic to cells, which is an important limiting factor for the biosynthesis of 2-PE. In this study, a novel 2-PE generating Meyerozyma sp. strain YLG18 was first isolated, which could produce 2-PE through both Ehrlich and Shikimate pathways. Moreover, the indigenous high 2-PE tolerance makes it a promising candidate for high 2-PE production. Response surface methodology and in situ product recovery technology could improve the final 2-PE production to 3.20 g/L, representing the highest 2-PE production by using Meyerozyma sp. Furthermore, genes involved in 2-PE synthesis were identified and their expression levels between Shikimate pathway and Ehrlich pathway were compared. Based on the genomic and transcriptional analysis, a penta-functional enzyme AroM and an aspartate aminotransferase (AAT) with the potential to convert phenylalanine into phenylpyruvate were identified. These findings would help broaden our knowledge and add the pool of known 2-PE generating microbes and genes.