Biosynthetic Methods Research Articles

Nature-based solution using a bioengineering strategy for soil erosion control in tropical climate with intense rainfall patterns

BackgroundIn the face of escalating soil erosion exacerbated by intense rainfall in tropical climates, the quest for sustainable and effective erosion control techniques is paramount. Nature-based solutions (NbS) using bioengineering strategies have emerged as a potential avenue, yet their efficacy and adaptability in such environmental conditions are not fully explored. ObjectiveThis study seeks to bridge the research gap by evaluating the effectiveness of a bioengineering approach, which involved a strategic plantation of Pigeonpea, Sesame, and Cowpea, as an NbS for soil erosion control under the challenging conditions of tropical climates. It emphasizes the rhizospheric characteristics of these species and their potential to offer a sustainable and environmentally friendly solution to soil erosion. MethodsEmploying a random block experimental design, the study compared the performance of Pigeonpea, Sesame, and Cowpea against conventional biosynthetic erosion control methods across various plots. Over 25 rainfall events, comprehensive data collection was undertaken, encompassing 150 measures of precipitation, surface runoff, and soil loss mass. Results: The findings reveal bioengineering solution's comparable, if not superior, effectiveness to conventional techniques, marked by minimal soil loss and enhanced water infiltration capabilities. Analysis of Covariance showcased a very large effect size, significantly underscoring bioengineering's efficacy in soil loss control. Notably, bioengineering's contribution extends beyond erosion control, fostering aquifer recharge and preventing sedimentation in water bodies. ConclusionsThis strategic plantation of Pigeonpea, Sesame, and Cowpea stands out as a promising NbS for soil erosion control in tropical climates, characterized by its sustainable approach and minimal environmental footprint. The study advocates for the broader integration of Pigeonpea, Sesame, and Cowpea in soil conservation practices, highlighting its potential to transform erosion control strategies towards greater environmental sustainability and effectiveness.

Rational engineering of homospermidine synthase for enhanced catalytic efficiency toward spermidine synthesis

Spermidine is a naturally occurring polyamine widely utilized in the prevention and treatment of various diseases. Current spermidine biosynthetic methods have problems such as low efficiency and complex multi-enzyme catalysis. Based on sequence-structure-function relationships, we engineered the widely studied homospermidine synthase from Blastochloris viridis (BvHSS) and obtained mutants that could catalyze the production of spermidine from 1,3-diaminopropane and putrescine. The specific activities of BvHSS and the mutants D361E and E232D + D361E (E232D-D) were 8.72, 46.04 and 48.30 U/mg, respectively. The optimal pH for both mutants was 9.0, and the optimal temperature was 50 °C. Molecular docking and dynamics simulations revealed that mutating aspartic acid at position 361 to glutamic acid narrowed the substrate binding pocket, promoting stable spermidine production. Conversely, mutating glutamic acid at position 232 to aspartic acid enlarged the substrate channel entrance, facilitating substrate entry into the active pocket and enhancing spermidine generation. In whole-cell catalysis lasting 6 h, D361E and E232D-D synthesized 725.3 and 933.5 mg/L of spermidine, respectively. This study offers a practical approach for single-enzyme catalyzed spermidine synthesis and sheds light on the crucial residues influencing homospermidine synthase catalytic activity in spermidine production.

Expanding structural diversity of 5'-aminouridine moiety of sansanmycin via mutational biosynthesis.

Sansanmycins represent a family of uridyl peptide antibiotics with antimicrobial activity specifically against Mycobacterium tuberculosis (including drug-resistant M. tuberculosis) and Pseudomonas aeruginosa. They target translocase I (MraY) to inhibit bacterial cell wall assembly. Given the unique mechanism of action, sansanmycin has emerged as a potential lead compound for developing new anti-tuberculosis drugs, while the 5'-aminouridine moiety plays a crucial role in the pharmacophore of sansanmycin. For expanding the structural diversity of the 5'-aminouridine moiety of sansanmycin through biosynthetic methods, we firstly demonstrated that SsaM and SsaK are responsible for the biosynthesis of the 5'-aminouridine moiety of sansanmycin in vivo. Using the ssaK deletion mutant (SS/KKO), we efficiently obtained a series of new analogues with modified 5'-aminouridine moieties through mutational biosynthesis. Based on molecular networking analysis of MS/MS, twenty-two new analogues (SS-KK-1 to -13 and SS-KK-A to -I) were identified. Among them, four new analogues (SS-KK-1 to -3 and SS-KK-C) were purified and bioassayed. SS-KK-2 showed better antibacterial activity against E. coli ΔtolC than the parent compound sansanmycin A. SS-KK-3 showed the same anti-TB activity as sansanmycin A against M. tuberculosis H37Rv as well as clinically isolated, drug-sensitive and multidrug-resistant M. tuberculosis strains. Furthermore, SS-KK-3 exhibited significantly improved structural stability compared to sansanmycin A. The results suggested that mutasynthesis is an effective and practical strategy for expanding the structural diversity of 5'-aminouridine moiety in sansanmycin.

Biosynthesis of L-fucose and L-fuculose using engineered Saccharomyces cerevisiae

Recently, L-fucose has received considerable attention as a potential cosmetic agent and substrate for human oligosaccharide synthesis. To date, only two methods have been reported for L-fucose biosynthesis: microbial biosynthesis based on the GDP-L-fucose pathway and enzymatic conversion using the L-fucose metabolic pathway enzymes. The lack of efficient biosynthetic methods has increased the price of L-fucose and other valuable chemicals synthesized from L-fucose. In this study, we introduced the L-fucose metabolic pathway from Escherichia coli into Saccharomyces cerevisiae and reverse-synthesized 7.75 mg/L L-fucose and 1.55 mg/L L-fuculose with lactaldehyde and glucose as substrates. L-fuculose was synthesized as a by-product of L-fucose biosynthesis. Conversion of lactaldehyde to 1,2 propanediol by an unknown oxidoreductase from S. cerevisiae is the bottleneck for fucose synthesis. To the best of our knowledge, this study is the first to reverse synthesize L-fucose and L-fuculose using whole cells via L-fucose metabolism.

Biosynthesis, Assembly, and Biomedical Applications of High-Performance Engineered Proteins.

Engineered structural proteins, mimicking the structure and function of well-characterized natural proteins, are of great interest for diverse applications due to their outstanding mechanical performance and hierarchical structures. Broad efforts have been devoted to developing novel toolsets of genetically engineered structural proteins to explore advanced protein-based materials. With the rational design and structural optimization of artificially structural proteins and the improved biosynthetic methods, artificial protein assemblies have demonstrated outstanding mechanical performance comparable to those of natural protein materials, showing promising biomedical applications. In this Review, we outline recent advances in the fabrication of high-performance protein materials, highlighting the roles of biosynthesis, structural modification, and assembly in optimizing the materials' properties. The relationship between hierarchical structures and the mechanical performance of these recombinant structural proteins is discussed in detail. We emphasize the biomedical applications of high-performance structural proteins and their assemblies in the fields of high-strength protein fibers and adhesives. Finally, we discuss the trends and perspectives for the development of structural protein-based materials.

Green Synthesis Optimization and Characterization of Selenium Nanoparticle Using Aqueous Extract of Peel Solanum Melongena L.

Recently, employing vegetable peel waste in green biosynthetic methods has received increased attention. It has low toxicity levels, is safe for the environment, and is simple to produce. The purpose of this research was to develop a sustainable technique of synthesizing SeNPs from an aqueous extract of eggplant peel. Because of this, selenium nanoparticles were produced in a single step utilizing an aqueous extract of peel Solanum melongena L. as a reducing and capping agent. The nanoparticles, which were studied using UV-Vis spectroscopy, had a surface Plasmon resonance centered at 320 nm. Nanoparticles sized between 50 and 150 nm were observed using a scanning electron microscope, while X-ray diffraction patterns revealed their amorphous, face-centered structure. Current research looks into how optimizing factors like reaction time, temperature, pH, selenous acid concentration, and reactant mixing ratio affect the quality of produced selenium nanoparticles. We found that 30 mM selenous acid, 30 degrees Celsius, pH 4, 9 days of incubation, and a 2:10 ratio of aqueous extract to selenous acid produced the highest quality selenium nanoparticles.

A New Combination Method of N-doped TiO2 Nanoparticles Synthesis for Heavy Metal Ions Cr(VI) Photoreduction Applications

Through a combination of biosynthetic and hydrothermal methods, N-doped TiO2 photocatalyst has been successfully synthesized using various concentrations of ammonia as a nitrogen source, namely 10% w/w (NTO10), 20% w/w (NTO20), 35% w/w (NTO35), and 50% w/w (NTO50). The synthesis of TiO2 was conducted using Aloe vera (L) Burm F. rind extract as a natural capping agent via the biosynthetic method, followed by a nitrogen doping process via the hydrothermal method. The X-ray Diffraction (XRD) analysis revealed that all phases were anatase. According to the results of the UV-Vis Diffuse Reflectance Spectroscopy (UV-Vis DRS) analysis using the Tauc-Plot method, all N-doped TiO2 samples showed a decrease in the energy gap compared to the TO sample. This indicates that the doping of TiO2 using nitrogen has been successfully doped into TiO2. The photocatalytic activity of N-doped TiO2 was evaluated for the photoreduction of the Cr(VI) model pollutant using a 24-watt LED lamp as a visible light source for 120 minutes. The results indicate that the NTO35 is the best-prepared N-doped TiO2, which showed a reduced rate for the Cr (VI) model pollutant of 50.88%, or two times greater than that of undoped TiO2.

Expanding the application of tryptophan: Industrial biomanufacturing of tryptophan derivatives.

Tryptophan derivatives are various aromatic compounds produced in the tryptophan metabolic pathway, such as 5-hydroxytryptophan, 5-hydroxytryptamine, melatonin, 7-chloro-tryptophan, 7-bromo-tryptophan, indigo, indirubin, indole-3-acetic acid, violamycin, and dexoyviolacein. They have high added value, widely used in chemical, food, polymer and pharmaceutical industry and play an important role in treating diseases and improving life. At present, most tryptophan derivatives are synthesized by biosynthesis. The biosynthesis method is to combine metabolic engineering with synthetic biology and system biology, and use the tryptophan biosynthesis pathway of Escherichia coli, Corynebacterium glutamicum and other related microorganisms to reconstruct the artificial biosynthesis pathway, and then produce various tryptophan derivatives. In this paper, the characteristics, applications and specific biosynthetic pathways and methods of these derivatives were reviewed, and some strategies to increase the yield of derivatives and reduce the production cost on the basis of biosynthesis were introduced in order to make some contributions to the development of tryptophan derivatives biosynthesis industry.

Current status and future perspectives on the biological production of polyhydroxyalkanoates

AbstractNowadays, the environmental pollution caused by conventional petroleum‐based plastics is one of the most serious problems facing mankind, and it is of great significance to look for alternative plastics with biodegradable feature. Notably, the bioplastics based on polyhydroxyalkanoates (PHA) have been a focus on research and development during the past several decades. In this review, the recent advances on the biological production of PHA were summarized, mainly including biosynthetic pathways and methods, followed by the extraction processes. Furthermore, the current status on PHA production using industrial waste streams was also discussed. For the moment, the relative higher production cost hindered the large‐scale biological production of PHA. Therefore, some insightful strategies were presented about the future research and scale production on biological production of PHA.

Efficient synthesis of 3D/2D CeO2/MoS2 nanocomposites with enhanced photocatalytic activity to degrade organic dye in wastewater and statistical optimization of reaction parameters

Nanocomposites synthesized by alternative approaches like biosynthetic methods are safer than those prepared by traditional chemical techniques. Further, this approach is both economically and environmentally feasible. In this study, we report an eco-friendly methodology for preparing cerium dioxide/molybdenum disulfide (CeO2/MoS2) nanocomposites. Moringa oleifera peel was used as the reducing/stabilizing agent for synthesizing CeO2 nanoparticles. The prepared nanocomposite was characterized using FT-IR analysis, SEM and EDAX analysis, TEM and SAED pattern analysis, X-Ray Diffraction Pattern, Zeta Potential, UV-Visible Diffuse Reflectance Spectra, X-Ray Photon Spectroscopy, and Photoluminescence spectra. Particle size and morphology were characterized by TEM and SEM. The photocatalytic pursuit of CeO2/MoS2 was explored by the degradation of methyl violet (MV) under visible light irradiation. Our methodology proved to be 96.25% effective in the degradation of MV. Further, we used this Response Surface Methodology for enhancing the process factors like volume of photocatalyst, time for degradation, and concentration of MV.

Modified Nucleotides for Chemical and Enzymatic Synthesis of Therapeutic RNA.

In recent years, RNA has emerged as a medium with a broad spectrum of therapeutic potential, however, for years, a group of short RNA fragments was studied and considered therapeutic molecules. In nature, RNA plays both functions, with coding and non-coding potential. For RNA, like any other therapeutic, to be used clinically, certain barriers must be crossed. Among them, there are biocompatibility, relatively low toxicity, bioavailability, increased stability, target efficiency and low off-target effects. In the case of RNA, most of these obstacles can be overcome by incorporating modified nucleotides into its structure. This may be achieved by both, in vitro and in vivo biosynthetic methods, as well as chemical synthesis. Some advantages and disadvantages of each approach are summarized here. The wide range of nucleotide analogues has been tested for their utility as monomers for RNA synthesis. Many of them have been successfully implemented, and a lot of pre-clinical and clinical studies involving modified RNA have been carried out. Some of these medications have already been introduced into clinics. After the huge success of RNA-based vaccines that were introduced into widespread use in 2020, and the introduction to the market of some RNA-based drugs, RNA therapeutics containing modified nucleotides appear to be the future of medicine.

The Effect of Different Synthesis with Chemical and Biological Methods on Properties of Silver Oxide Nanoparticles

Silver oxide (Ag2O) nanoparticles have been successfully synthesized through several methods, namely sol-gel, sonochemical, and biological methods. X-ray diffraction studies revealed that the sonochemical method produces silver oxide with high phase purity, then the sol-gel method produces another phase, namely silver crystals, while the biological method produces Ag3PO4 phase from the precursor media. The research showed that the sol-gel method had the smallest crystallite and particle sizes of 9.5 and 232.7 nm, respectively, compared to sonochemical and biological methods. It is known that the specific surface area of the sol-gel method has the largest value, namely 60.09 m2/g, compared to the sonochemical and biosynthetic methods, which are 51.78 and 24.77 m2/g, respectively. Scanning electron microscopy study showed homogeneous spherical nanoparticles of silver oxide in the sol-gel and sonochemical methods, however, the biological method resulted in the formation of non-spherical silver oxide nanoparticles in the form like flakes. HIGHLIGHTS Synthesis of silver oxide by chemical method produces pure silver oxide crystals, smaller crystallite size, larger specific area, and more homogeneous particle size than biological methods The sol-gel method for the synthesis of silver oxide produces the smallest particle size than the sonochemical and biological methods The sonochemical method produces the highest crystallinity and size homogeneity compared to the sol-gel and biological methods GRAPHICAL ABSTRACT

The 'emodin family' of fungal natural products-amalgamating a century of research with recent genomics-based advances.

Covering: up to 2022A very large group of biosynthetically linked fungal secondary metabolites are formed via the key intermediate emodin and its corresponding anthrone. The group includes anthraquinones such as chrysophanol and cladofulvin, the grisandienes geodin and trypacidin, the diphenyl ether pestheic acid, benzophenones such as monodictyphenone and various xanthones including the prenylated shamixanthones, the agnestins and dimeric xanthones such as the ergochromes, cryptosporioptides and neosartorin. Such compounds exhibit a wide range of bioactivities and as such have been utilised in traditional medicine for centuries, as well as garnering more recent interest from the pharmaceutical sector. Additional interest comes from industries such as textiles and cosmetics due to their use as natural colourants. A variety of biosynthetic routes and mechanisms have been proposed for this family of compounds, being altered and updated as new biosynthetic methods develop and new results emerge. After nearly 100 years of such research, this review aims to provide a comprehensive overview of what is currently known about the biosynthesis of this important family, amalgamating the early chemical and biosynthetic studies with the more recent genetics-based advances and comparative bioinformatics.

Показатели качества гороховых и нутовых белковых концентратов

Protein deficiency in human and animal diet demands novel protein components, e.g., various leguminous concentrates. This article compares the quality indicators of food and feed protein concentrates obtained by biotechnological and biosynthetic methods from pea and chickpea flour.
 The research featured pea and chickpea protein concentrates; enzyme preparations Shearzym 500 L, Viscoferm L, Fungamyl 800 L, and Alcalase 2.4 L (Denmark); Saccharomyces and Geotrichum micromycetes yeasts. The protein concentrates were obtained from pea and chickpea flour using a new technology developed by the authors. The properties of the protein concentrates were studied by chemical, physicochemical, biochemical, and microbiological research methods.
 The research resulted in new protein concentrates for human diet and microbial-vegetable feed concentrates. The protein content was 83.22 ± 0.35% on dry basis in the chickpea protein concentrate and 71.78 ± 0.35% on dry basis in the pea concentrate. The indicator of biological value, adjusted for protein digestibility, was 96% for the pea protein concentrate and 76% for the chickpea protein concentrate. The resulting protein concentrates differed in the content of essential amino acids, copper, cobalt, manganese, and nickel, as well as in phenolic acids and their derivatives. The chickpea concentrate had a greater foaming capacity and lower foam stability, which correlated with a greater content of phenolic acids, their derivatives, parallel β-structures, and antiparallel protein 310-helices. Both the concentrates had the same results in assimilating whey carbohydrates by the consortium of Saccharomyces and G. micromycete. Both types of the dry feed biomass contained 61.68–64.10% protein on dry basis, while the biomasses with culture liquid contained 47.15–51.09% protein on dry basis. The biologically complete feed concentrates differed in the mass fraction of fat, soluble and insoluble fibers, minerals, and fatty acids. The amounts of phenolic acids and their derivatives (mg/g of protein) in the raw materials and the concentrates correlated with the optical density of their aqueous solutions at D590 nm and the color of the preparations (R = 0.895).
 The new pea and chickpea flour protein concentrates can be recommended as human food components, while the microbial-vegetable concentrates from pea and chickpea serum can improve the quality of raw materials of animal origin in animal feed.

Biochemical changes caused by Zinc oxide Nanoparticles synthesized using Ficus thonningii extract in induced diabetic Wistar Albino Rats

Green synthesis of nanoparticles known as the synthesis of nanoparticles using biosynthetic methods involving naturally reducing agents such as polysaccharides, biological microorganism such as bacteria and fungus or plants extract. The synthesis of nanoparticles by the use of biological methods have reached a colossal signification above physical and chemical procedures, this is due to the use of innocuous, biocompatible, and ecologically-sound substrates and remarkably uncomplicated synthetic processes at encompassing conditions. In this research, the synthesis, characterization and the determination of the antibacterial activity of Zinc oxide Nanoparticles (ZnO NPs) was ascertained using stem bark extract of Ficus thonningii (Blume) as a stabilizing agent. However, the anti-diabetic activity and some biochemical changes caused by the synthesized ZnO NPs on alloxan-induced diabetic Wistar Rats were also determined. ZnO NPs were synthesized using biological method at different concentrations of ZnO solution (1mM, 2mM, 3mM and 4mM), these NPs were characterized using UV-visible spectroscopy, FTIR and SEM. Wistar rats weight 185 ± 5g were grouped into nine (9) groups (A, B, C, D, E, F, G, and I). Group A served as normal control which was given only feed and water, group B, C, D and E, were induce and treated with 1mM, 2mM, 3mM and 4mM ZnONPs respectively, then F and G were induced and treated with aqueous extract and ethanolic extract while H was induced and treated with Glibenclamide (standard drug for diabetes) by gavage method and finally I was induced and untreated which served as diabetic control. The results showed that ZnO NPs were synthesized with the indication of the change in colour from yellow to dark brown colour. The UV-visible spectroscopy was taken at range between 200nm to 700nm which displayed different peaks at the range of 209nm to 383nm. However, the FTIR showed the existence of various functional groups such as C=C stretch, C≡C stretch and Alcohol OH stretch representing the bioactive compounds such as phenol, amine and many others. The Nanoparticles were analyzed with SEM to examine the morphology of the Nanoparticles. The diabetic induced rats revealed significant decrease in fasting blood glucose after treatment compared with the diabetic untreated rats, the doses were effective when compared with Glibenclamide treated rats. The levels of serum Alkaline phosphatase, Alanine Amino transferase, Albumin, Globulin, Bilirubin, Total Protein, Urea, Creatinine and Electrolytes concentrations displayed no significant increase relative to diabetic control (p < 0.05; n ≥ 5).

Role of Phytoconstituents in the Aloe-Mediated Nanoparticles

Currently, green, single-pot biomimetic, and/or biological methods of Nanoparticle (NP) synthesis are preferred over chemical and physical methods because of their rapidity, eco-friendliness, non-pathogenicity, and economic attributes. In addition, these biosynthesis methods exclude the use of high temperature, energy, pressure, and toxic chemicals. Through biosynthetic methods, nanotechnology is related to biotechnology. This has advanced nanobiotechnology which is the development of eco-friendly and biosynthetic nanomaterials/nanoparticles. Therefore, nowadays, biogenic or green synthesis of NPs using plants has emerged as a potential nano-factory, and their applications are based on phytochemicals. The chemical constituents identified in Aloe plants include vitamins, minerals, enzymes, polysaccharides, fatty acids, indoles, hydrocarbons, carboxylic acids, aldehydes, ketones, phenolic compounds, phytosterols, pyrimidines, alkaloids, etc. Each of these chemicals has potential biological activities that make them essential for in nanotechnology. Aloe phytochemicals play a crucial role in the fabrication of Aloe-based NPs by acting as reducing, capping, and stabilizing agents that control the shape and size of the formed NPs. In addition, these phytochemicals play a significant role in the applications of Aloe-based NPs owing to their biological properties. Moreover, it is important to understand the role of phytoconstituents from different Aloe species and in every part of the plants using nanotechnology.

Chitin oligosaccharides for the food industry: production and applications

Chitin oligosaccharides (CHOS), high-value-added oligomers linked by N-acetyl-d-glucosamine (GlcNAc, NAG), and a small amount of d-glucosamine (GlcN, GA), have aroused increasing interest due to their excellent biological properties, including antibacterial, anti-inflammatory, and immunoprotective activities, and intestinal regulation. The efficient production and utilization of CHOS with high performance can solve problems from chitin as biowaste. However, the large-scale production of well-defined CHOS has not been fully accomplished due to the limited biotechnology and separation methods, thus impeding the research on their biological functions as well as their accurate applications. In this review, we comprehensively summarize the current preparation methods of CHOS, including the chemical, physical, enzymatic and biosynthetic methods. The advantages and disadvantages of the methods are discussed in terms of efficiency, economy, and environmental effects. Furthermore, the applications of CHOS in the food industry and their contributions to human health based on their excellent bioactivities are expounded. It is hoped that this review will help in providing new insights into the production of CHOS with high precision, and support the application of CHOS in serving the food industry as nutritional supplements or foods for special medical purposes.

Unravelling the Structural Development of Peptide‐Coordinated Iron‐Sulfur Clusters: Prebiotic Evolution and Biosynthetic Strategies

Comprehensive SummaryIron‐sulfur (Fe‐S) proteins are among the most common type of natural metalloproteins that participate in a large range of key metabolic processes. To date, enormous research works on the exploration of protein structures and catalytic mechanisms have revealed that the active sites are generally composed of a Fe‐S cluster and a highly conserved coordination environment. Accordingly, people are enlightened by the prebiotic evolution of ancient clusters and are dedicated to the development of biosynthetic methods for modern clusters. This review aims to systemically summarize the structural development of peptide‐coordinated iron‐sulfur clusters from two perspectives: “bottom‐up” approaches involving evolution of prebiotic chemical synthesis for natural proteins and “top‐down” analyses of biosynthesis in modern biological systems for artificial metalloproteins. Moreover, current challenges and the direction of future development are also presented to provide new perspectives of developing enzyme mimics and further mechanistic studies.

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. Glutamate decarboxylase (GAD) transforms L-glutamate to GABA using pyridoxal 5′-phosphate (PLP) as a cofactor. Bioconversion of GABA with whole cells overexpressing the glutamate decarboxylase has advantages of fewer byproducts and rapid reaction. However, there is a bottleneck in the whole-cell bioconversion system i.e., higher GABA production require a large amount of cofactor PLP which make the process costly. Therefore, pyridoxal kinase (PdxY) able to regenerate PLP was introduced in the whole-cell system to construct a new GABA producing system. Culture and reaction conditions were optimized, and 100% conversion of 0.6 M MSG was obtained. This study reports that a competitive level of GABA production could be achieved without supplying additional PLPs.

Authentication of vanillin ex glucose – A first study on the influence of the glucose-source on the δ13C and δ2H value

Vanillin is the most characteristic compound in vanilla flavour. Since vanilla pods are very expensive, vanillin is mainly produced by synthetic and sometimes biosynthetic methods. Biosynthetic vanillin is called ‘biovanillin’ and can -by law-be labelled as ‘natural’. The isotopic carbon ratio (expressed as δ 13 C) is a widely established and valuable authentication parameter for vanillin. Furthermore, currently available data about δ 2 H values indicate, that the isotopic hydrogen ratio can make a decisive contribution to the authentication of vanillin. One of the most recent developments is the bio-production of vanillin derived from glucose. However, very little is known about its isotopic composition. Here, we present the δ 13 C and δ 2 H values of glucose from corn and wheat and the vanillin that was derived from these. The isotopic composition of the glucose is clearly reflected in the resulting vanillin molecule. All ‘glucose-vanillin’ samples could be distinguished from vanillin originating from other sources when combining the δ 13 C and δ 2 H value. • Carbon and hydrogen isotopic ratio characterisation of vanillin ex glucose. • Carbon and hydrogen isotopic ratio characterisation of glucose from wheat and corn. • The isotopic composition of the glucose is reflected in the derived vanillin.