Microbial production of levulinic acid from glucose by engineered Pseudomonas putida KT2440.

Levulinic acid(LA) is produced through acid-catalyzed hydrolysis and dehydration of lignocellulosic biomass. It is a key platform chemical used as an intermediate in various industries including biofuels, cosmetics, pharmaceuticals, and polymers. Traditional LA production uses chemical conversion, which requires high temperatures and pressures, strong acids, and produces undesirable side reactions, repolymerization products, and waste problems Therefore, we designed an integrated process to produce LA from glucose through metabolic engineering of Pseudomonas putida KT2440.

Enhanced theanine production with reduced ATP supply by alginate entrapped Escherichia coli co-expressing γ-glutamylmethylamide synthetase and polyphosphate kinase.

L-theanine is an amino acid with a unique flavor and many therapeutic effects. Its enzymatic synthesis has been actively studied and γ-Glutamylmethylamide synthetase (GMAS) is one of the promising enzymes in the biological synthesis of theanine. However, the theanine biosynthetic pathway with GMAS is highly ATP-dependent and the supply of external ATP was needed to achieve high concentration of theanine production.

Catalytic hydrolysis of agar using magnetic nanoparticles: optimization and characterization.

Background: Agar is used as a gelling agent that possesses a variety of biological properties; it consists of the polysaccharides agarose and porphyrin. In addition, the monomeric sugars generated after agar hydrolysis can be functionalized for use in biorefineries and biofuel production. The main objective of this study was to develop a sustainable agar hydrolysis process for bioethanol production using nanotechnology.

Application of liquid-based colorimetric method for high throughput screening of bioplastic-degrading strains using esterase assay.

To alleviate environmental problems caused by using conventional plastics, bioplastics have garnered significant interest as alternatives to petroleum-based plastics. Despite possessing better degradability traits compared to traditional plastics, the degradation of bioplastics still demands a longer duration than initially anticipated. This necessitates the utilization of degradation strains or enzymes to enhance degradation efficiency, ensuring timely degradation.

Enhanced production of glutaric acid by biocatalyst-recycled bioconversion process integrated with in situ product recovery by adsorption.

Product inhibition caused by organic acids is a serious issue in establishing economical biochemical production systems. Herein, for enhanced production of glutaric acid by overcoming product inhibition triggered by glutaric acid, a whole-cell bioconversion system equipped with biocatalyst recycling process and in situ product recovery by adsorption was developed successfully. From the whole-cell bioconversion reaction, we found that both dissociated and undissociated forms of glutaric acid acted as an inhibitor in the whole-cell bioconversion reaction, wherein bioconversion was hindered beyond 200 mM glutaric acid regardless of reaction pH.

Poly(3-hydroxybutyrate) Degradation by sp. Isolated from Soil and Identification of and Expressing PHB Depolymerase.

Poly(3-hydroxybutyrate) (PHB) is a biodegradable and biocompatible bioplastic. Effective PHB degradation in nutrient-poor environments is required for industrial and practical applications of PHB. To screen for PHB-degrading strains, PHB double-layer plates were prepared and three new species with PHB-degrading ability were isolated from the soil.

Continuous production of gamma aminobutyric acid by engineered and immobilized Escherichia coli whole-cells in a small-scale reactor system.

γ-Amino butyric acid (GABA) is a non-proteinogenic amino acid and a human neurotransmitter. Recently, increasing demand for food additives and biodegradable bioplastic monomers, such as nylon 4, has been reported. Consequently, considerable efforts have been made to produce GABA through fermentation and bioconversion.

β-Ketoadipic acid production from poly(ethylene terephthalate) waste chemobiological upcycling.

The upcycling of poly(ethylene terephthalate) (PET) waste can simultaneously produce value-added chemicals and reduce the growing environmental impact of plastic waste. In this study, we designed a chemobiological system to convert terephthalic acid (TPA), an aromatic monomer of PET, to β-ketoadipic acid (βKA), a C6 keto-diacid that functions as a building block for nylon-6,6 analogs. Using microwave-assisted hydrolysis in a neutral aqueous system, PET was converted to TPA with Amberlyst-15, a conventional catalyst with high conversion efficiency and reusability.

Recent Advances in the Chemobiological Upcycling of Polyethylene Terephthalate (PET) into Value-Added Chemicals.

Polyethylene terephthalate (PET) is a plastic material commonly applied to beverage packaging used in everyday life. Owing to PET's versatility and ease of use, its consumption has continuously increased, resulting in considerable waste generation. Several physical and chemical recycling processes have been developed to address this problem.

Production of γ-Aminobutyrate (GABA) in Recombinant by Expression of Glutamate Decarboxylase Active at Neutral pH.

γ-Aminobutyrate (GABA) is an important chemical by itself and can be further used for the production of monomer used for the synthesis of biodegradable polyamides. Until now, GABA production using harboring glutamate decarboxylases (GADs) has been limited due to the discrepancy between optimal pH for GAD activity (pH 4.0) and cell growth (pH 7.

Development of a glutaric acid production system equipped with stepwise feeding of monosodium glutamate by whole-cell bioconversion.

In the bioproduction of glutaric acid, an emerging bioplastic monomer, α-ketoglutaric acid (α-KG) is required as an amine acceptor for 4-aminobutyrate aminotransferase (GabT)-driven conversion of 5-aminovalerate (5-AVA) to glutarate semialdehyde. Herein, instead of using expensive α-KG, an indirect α-KG supply system was developed using a relatively cheap alternative, monosodium glutamate (MSG), for l-glutamate oxidase (Gox)-based whole-cell conversion. Using 200 mM 5-AVA and 30 mM MSG initially with Gox, 67.

Microbial production of 2-pyrone-4,6-dicarboxylic acid from lignin derivatives in an engineered Pseudomonas putida and its application for the synthesis of bio-based polyester.

Lignin valorization depends on microbial upcycling of various aromatic compounds in the form of a complex mixture, including p-coumaric acid and ferulic acid. In this study, an engineered Pseudomonas putida strain utilizing lignin-derived monomeric compounds via biological funneling was developed to produce 2-pyrone-4,6-dicarboxylic acid (PDC), which has been considered a promising building block for bioplastics. The biosynthetic pathway for PDC production was established by introducing the heterologous ligABC genes under the promoter P in a strain lacking pcaGH genes to accumulate a precursor of PDC, i.

Gamma aminobutyric acid (GABA) production in Escherichia coli with pyridoxal kinase (pdxY) based regeneration system.

Gamma-aminobutyric acid (GABA) is a non-proteinogenic amino acid act as a major neurotransmitter inhibitor in the nervous system of mammals. It also used as a precursor of bioplastics synthesis such as N-methylpyrolidone and polyamide 4. Chemical-based synthesis methods have many environmental-related issues, so efforts have been made to develop biosynthetic methods to produce GABA.

Chemoautotroph Cupriavidus necator as a potential game-changer for global warming and plastic waste problem: A review.

Cupriavidus necator, a versatile microorganism found in both soil and water, can have both heterotrophic and lithoautotrophic metabolisms depending on environmental conditions. C. necator has been extensively examined for producing Polyhydroxyalkanoates (PHAs), the promising polyester alternatives to petroleum-based synthetic polymers because it has a superior ability for accumulating a considerable amount of PHAs from renewable resources.

Chemo-Biological Upcycling of Poly(ethylene terephthalate) to Multifunctional Coating Materials.

Chemo-biological upcycling of poly(ethylene terephthalate) (PET) developed in this study includes the following key steps: chemo-enzymatic PET depolymerization, biotransformation of terephthalic acid (TPA) into catechol, and its application as a coating agent. Monomeric units were first produced through PET glycolysis into bis(2-hydroxyethyl) terephthalate (BHET), mono(2-hydroxyethyl) terephthalate (MHET), and PET oligomers, and enzymatic hydrolysis of these glycolyzed products using Bacillus subtilis esterase (Bs2Est). Bs2Est efficiently hydrolyzed glycolyzed products into TPA as a key enzyme for chemo-enzymatic depolymerization.

Erratum: Validation Study of the Official Korean Version of the Movement Disorder Society-Unified Parkinson's Disease Rating Scale.

This corrects the article on p. 633 in vol. 16, PMID: 33029970.

Improving the organic solvent resistance of lipase a from Bacillus subtilis in water-ethanol solvent through rational surface engineering.

Given that lipase is an enzyme applicable in various industrial fields and water-miscible organic solvents are important reaction media for developing industrial-scale biocatalysis, a structure-based strategy was explored to stabilize lipase A from Bacillus subtilis in a water-ethanol cosolvent. Site-directed mutagenesis of ethanol-interacting sites resulted in 4 mutants, i.e.

Validation Study of the Official Korean Version of the Movement Disorder Society-Unified Parkinson's Disease Rating Scale.

Background And Purpose: The Movement Disorder Society-Sponsored Revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) is widely used for estimating the symptoms of Parkinson's disease. Translation and validation of the MDS-UPDRS is necessary for non-English speaking countries and regions. The aim of this study was to validate the Korean version of the MDS-UPDRS.

Double-Blind, Randomized, Placebo-Controlled Trial of DA-9701 in Parkinson's Disease: PASS-GI Study.

Objectives: This study aimed to assess the efficacy of DA-9701 on gastrointestinal symptom-related quality of life in patients with Parkinson's disease on stable dopaminergic medications.

Methods: This multicenter, double-blind, placebo-controlled, phase 4 trial included a total of 144 patients with Parkinson's disease with gastrointestinal dysfunctions based on predefined criteria. Participants were randomized to take either DA-9701 or placebo for 4 weeks, and then both groups were administered DA-9701 for an additional 8 weeks while antiparkinsonian medications were unchanged.

Neuropsychiatric Traits Associated with Refractory Impulse Control Disorder in Parkinson's Disease.

Introduction: Impulse control disorder (ICD) in Parkinson's disease (PD) is a critical nonmotor symptom with personality or neuropsychiatric traits contributing to ICD.

Objective: This study aimed to identify predictive traits for persistent or paradoxical aggravation of ICD after dopamine agonist substitution therapy for ICD in PD.

Methods: We conducted a case-control study using a database of a multicenter intervention trial for ICD in PD.

Recent Advances in Sustainable Plastic Upcycling and Biopolymers.

Advances in scientific technology in the early twentieth century have facilitated the development of synthetic plastics that are lightweight, rigid, and can be easily molded into a desirable shape without changing their material properties. Thus, plastics become ubiquitous and indispensable materials that are used in various manufacturing sectors, including clothing, automotive, medical, and electronic industries. However, strong physical durability and chemical stability of synthetic plastics, most of which are produced from fossil fuels, hinder their complete degradation when they are improperly discarded after use.

Biosynthesis of polyhydroxyalkanoates from sucrose by metabolically engineered Escherichia coli strains.

Sucrose utilization has been established in Escherichia coli strains by expression of Mannheimia succiniciproducens β-fructofuranosidase (SacC), which hydrolyzes sucrose into glucose and fructose. Recombinant E. coli strains that can utilize sucrose were examined for their abilities to produce poly(3-hydroxybutyrate) [P(3HB)] and poly(3-hydroxybutyrate-co-lactate) [P(3HB-co-LA)] from sucrose.