The Experts below are selected from a list of 32016 Experts worldwide ranked by ideXlab platform

Alexander Steinbuchel - One of the best experts on this subject based on the ideXlab platform.

  • application of the bpec pathway for large scale Biotechnological Production of poly 3 mercaptopropionate by recombinant escherichia coli including a novel in situ isolation method
    Applied and Environmental Microbiology, 2005
    Co-Authors: Nehal Thakor, Tina Lutkeeversloh, Alexander Steinbuchel
    Abstract:

    Metabolically engineered Escherichia coli JM109 harboring plasmid pBPP1 and expressing the nonnatural BPEC pathway for synthesis of thermoplastic polyhydroxyalkanoates (PHA) and novel polythioesters (PTE) to provide suitable substrates of PHA synthase was investigated with respect to Biotechnological Production of poly(3-mercaptopropionate) [poly(3MP)]. Fed-batch fermentation processes were established at the 30- and 500-liter scales in stirred tank bioreactors to produce kilogram amounts of poly(3MP). Cultivation was done in a modified M9 mineral salts medium containing glucose or glycerol as the carbon and energy source and with 3-mercaptopropionic acid (3MP) as the precursor substrate for poly(3MP) biosynthesis provided from the late exponential growth phase. Approximately 23 g of cell dry matter (CDM) per liter and poly(3MP) cell contents of up to 45% (wt/wt) were the highest cell densities and polymer contents obtained, respectively. At best, 69.1% (wt/wt) of 3MP was converted into poly(3MP), indicating that 3MP was mostly used for poly(3MP) biosynthesis. Furthermore, a novel in situ process for rapid and convenient isolation of poly(3MP) from the cells in the bioreactor was developed. This was achieved by addition of sodium dodecyl sulfate to the cultivation broth immediately after the fermentation, heating to 90°C for 20 min with intensive stirring, and subsequent washing steps. The purity of such in situ isolated poly(3MP) was more than 98%, as revealed by gas chromatographic and elemental sulfur analyses of the material isolated.

  • metabolic engineering and pathway construction for Biotechnological Production of relevant polyhydroxyalkanoates in microorganisms
    Biochemical Engineering Journal, 2003
    Co-Authors: Alexander Steinbuchel, Tina Lutkeeversloh
    Abstract:

    Abstract Prokaryotes synthesize a wide range of different polyhydroxyalkanoic acids (PHA) and accumulate these polyesters as insoluble inclusions in the cytoplasm for storage of carbon and energy. PHAs are considered for various technical applications due to interesting physical and material properties. In order to establish economically feasible Biotechnological Production systems and to obtain PHAs from cheap carbon sources with a preference from renewable resources, CO2 or residual materials, efforts are undertaken to engineer novel pathways in recombinant prokaryotic and eukaryotic organisms. This requires transfer of a PHA synthase structural gene, expression of an enzymatically active PHA synthase protein and in particular engineering of pathways that provide this key enzyme of PHA synthesis with suitable substrates at sufficient concentrations. Only if all three aspects are well considered, a functional active PHA biosynthesis pathway will be expressed allowing PHA biosynthesis from central intermediates and therefore Biotechnological Production from renewable carbon sources or even CO2. This review will focus on the engineering of pathways resulting in the formation of PHAs containing 3-hydroxyvaleric acid, medium-chain-length 3-hydroxyalkanoic acids or 4-hydroxybutyric acid as constituents.

  • Biotechnological Production of vanillin
    Applied Microbiology and Biotechnology, 2001
    Co-Authors: Horst Priefert, Jurgen Rabenhorst, Alexander Steinbuchel
    Abstract:

    Vanillin is one of the most important aromatic flavor compounds used in foods, beverages, perfumes, and pharmaceuticals and is produced on a scale of more than 10 thousand tons per year by the industry through chemical synthesis. Alternative biotechnology-based approaches for the Production are based on bioconversion of lignin, phenolic stilbenes, isoeugenol, eugenol, ferulic acid, or aromatic amino acids, and on de novo biosynthesis, applying fungi, bacteria, plant cells, or genetically engineered microorganisms. Here, the different biosynthesis routes involved in Biotechnological vanillin Production are discussed.

  • Perspectives for Biotechnological Production and Utilization of Biopolymers: Metabolic Engineering of Polyhydroxyalkanoate Biosynthesis Pathways as a Successful Example
    Macromolecular Bioscience, 2001
    Co-Authors: Alexander Steinbuchel
    Abstract:

    This article provides an overview of biopolymers, classed according to their chemical structures, function and occurrence, the principles of biosynthesis and metabolism in organisms. It will then focus on polyhydroxyalkanoates (PHA) for which technical applications in several areas are currently considered. PHAs represent a complex class of bacterial polyesters consisting of various hydroxyalkanoic acids that are synthesized by bacteria as storage compounds for energy and carbon if a carbon source is present in excess. Poly(3-hydroxybutyrate), poly(3HB), is just one example. Most other PHAs are only synthesized if pathways exist which mediate between central intermediates of the metabolism or special precursor substrates on one side and coenzyme A thioesters of hydroxyalkanoic acids, which are the substrates of the PHA synthase catalyzing the polymerization, on the other side. During the last decade, basic and applied research have revealed much knowledge about the biochemical and molecular basis of the enzymatic processes for the synthesis of PHAs in microorganisms. The combination of detailed physiological studies, utilization of the overwhelming information provided by the numerous genome sequencing projects, application of recombinant DNA technology, engineering of metabolic pathways or enzymes and molecular breeding techniques applied to plants have provided new perspectives to produce these technically interesting biopolymers by novel or significantly improved Biotechnological processes or by agriculture. Some examples for successful in vivo and in vitro engineering of pathways suitable for the synthesis and Biotechnological Production of PHAs consisting of medium-chain-length 3-hydroxyalkanoic acids and short-chain-length hydroxyalkanoic acids will be provided.

Karlheinz Drauz - One of the best experts on this subject based on the ideXlab platform.

  • Biotechnological Production of amino acids and derivatives: current status and prospects
    Applied Microbiology and Biotechnology, 2005
    Co-Authors: Wolfgang Leuchtenberger, Klaus Huthmacher, Karlheinz Drauz
    Abstract:

    For almost 50 years now, Biotechnological Production processes have been used for industrial Production of amino acids. Market development has been particularly dynamic for the flavor-enhancer glutamate and the animal feed amino acids l -lysine, l -threonine, and l -tryptophan, which are produced by fermentation processes using high-performance strains of Corynebacterium glutamicum and Escherichia coli from sugar sources such as molasses, sucrose, or glucose. But the market for amino acids in synthesis is also becoming increasingly important, with annual growth rates of 5–7%. The use of enzymes and whole cell biocatalysts has proven particularly valuable in Production of both proteinogenic and nonproteinogenic l -amino acids, d -amino acids, and enantiomerically pure amino acid derivatives, which are of great interest as building blocks for active ingredients that are applied as pharmaceuticals, cosmetics, and agricultural products. Nutrition and health will continue to be the driving forces for exploiting the potential of microorganisms, and possibly also of suitable plants, to arrive at even more efficient processes for amino acid Production.

Mo Xia - One of the best experts on this subject based on the ideXlab platform.

  • metabolic engineering of escherichia coli for Biotechnological Production of high value organic acids and alcohols
    Applied Microbiology and Biotechnology, 2011
    Co-Authors: Yuji Cao, Huibi Zou, Mo Xia
    Abstract:

    Confronted with the gradual and inescapable exhaustion of the earth’s fossil energy resources, the bio-based process to produce platform chemicals from renewable carbohydrates is attracting growing interest. Escherichia coli has been chosen as a workhouse for the Production of many valuable chemicals due to its clear genetic background, convenient to be genetically modified and good growth properties with low nutrient requirements. Rational strain development of E. coli achieved by metabolic engineering strategies has provided new processes for efficiently Biotechnological Production of various high-value chemical building blocks. Compared to previous reviews, this review focuses on recent advances in metabolic engineering of the industrial model bacteria E. coli that lead to efficient recombinant biocatalysts for the Production of high-value organic acids like succinic acid, lactic acid, 3-hydroxypropanoic acid and glucaric acid as well as alcohols like 1,3-propanediol, xylitol, mannitol, and glycerol with the discussion of the future research in this area. Besides, this review also discusses several platform chemicals, including fumaric acid, aspartic acid, glutamic acid, sorbitol, itaconic acid, and 2,5-furan dicarboxylic acid, which have not been produced by E. coli until now.

Susan Krull - One of the best experts on this subject based on the ideXlab platform.

  • Biotechnological Production of itaconic acid-things you have to know.
    Applied microbiology and biotechnology, 2018
    Co-Authors: Anja Kuenz, Susan Krull
    Abstract:

    Itaconic acid is one of the basic chemicals for the polymer industry, which can be produced on the basis of renewable raw materials. Since the middle of the twentieth century, itaconic acid has been produced industrially using the filamentous fungus Aspergillus terreus. But the demand for the organic acid is low due to the high Production costs compared to alternative petrochemical manufactured raw materials. The high Production costs are based on a low final titer, low productivities, and the usage of pure sugars, purified molasses, or starch hydrolysates, since the fungus reacts very sensitively to impurities in a culture medium. This review provides a comprehensive overview of the most recent developments, including a spectrum of studied microorganisms and their capabilities for the Production of itaconic acid. The technological achievements in the Biotechnological Production of itaconic acid are presented. Particular attention is paid to current achievements in terms of suitable alternative substrates and their applicability in fermentation processes. Also, the pathway of itaconic acid and especially the influences on the fermentation process, which must be known in order to achieve a high final titer of itaconic acid, a yield close to the theoretical yield, and high productivity.

Jie Chen - One of the best experts on this subject based on the ideXlab platform.

  • Biotechnological Production of alpha-keto acids: Current status and perspectives
    Bioresource Technology, 2016
    Co-Authors: Yang Song, G. Du, Jianghua Li, Long Liu, Hyun Dong Shin, Jie Chen
    Abstract:

    Alpha-keto (α-keto) acids are used widely in feeds, food additives, pharmaceuticals, and in chemical synthesis processes. Although most α-keto acids are currently produced by chemical synthesis, their Biotechnological Production from renewable carbohydrates is a promising new approach. In this mini-review, we first present the different types of α-keto acids as well as their applications; next, we summarize the recent progresses in the Biotechnological Production of some important α-keto acids; namely, pyruvate, α-ketoglutarate, α-ketoisovalerate, α-ketoisocaproate, phenylpyruvate, α-keto-γ-methylthiobutyrate, and 2,5-diketo-D-gluconate. Finally, we discuss the future prospects as well as favorable directions for the Biotechnological Production of keto acids that ultimately would be more environment-friendly and simpler compared with the Production by chemical synthesis.

  • Biotechnological Production of pyruvic acid
    Applied Microbiology and Biotechnology, 2001
    Co-Authors: Y X Li, Y Li, Jie Chen, Song Yong Lun
    Abstract:

    Pyruvic acid is an important organic acid widely used in the chemical and drug, as well as agrochemical, industries. Compared with the chemical method, Biotechnological Production of pyruvic acid is an alternative approach because of the low cost. An overview of Biotechnological Production of pyruvate, including direct fermentative Production employing eukaryotic and prokaryotic microorganisms, Production by a resting cell method and an enzymatic method as well as the recovery of pyruvate, is discussed. A multi-vitamin auxotrophic yeast strain, Torulopsis glabrata. has been used in the commercial Production of pyruvate; emphasis is therefore placed on the mechanism and characteristics of pyruvate Production by this strain.