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Biocatalyst recombining methods

The above two processes employ isolated enzymes - penicillin G acylase and thermolysin, respectively - and the key to their success was an efficient production of the enzyme. In the past this was often an insurmountable obstacle to commercialization, but the advent of recombinant DNA technology has changed this situation dramatically. Using this workhorse of modern biotechnology most enzymes can be expressed in a suitable microbial host, which enables their efficient production. As with chemical catalysts another key to success often is the development of a suitable immobilization method, which allows for efficient recovery and recycling of the biocatalyst. [Pg.50]

Galan Sicilia, B., et al., Method for Desulfurization of Dibenzothiophene Using a Recombinant Pseudomonas Putida Strain as Biocatalyst Patent No. W00170996. 2002, June 16. [Pg.216]

A BDS method using a transformed microorganism containing a recombinant DNA molecule of Rhodococcus origin. This transformed microorganism expresses a BDS-active biocatalyst. (Use in BDS of the biocatalyst protected in Refs. [37-39])... [Pg.301]

PEC. The patent includes the production method for the biocatalyst, with a characteristic inhibitory effect on certain enzyme expression. The expression recombinant vector contains a promoter free from manifesting inhibition due to an inorganic sulfur compound or a sulfur-containing amino acid. The recombinant microorganism also contains a gene for desulfurizing the sulfur-containing heterocyclic compound. [Pg.341]

All these techniques create genetic diversity by recombination and point mutations and are well developed. However, insertions and deletions (indels) are also important types of mutation which are probably underrepresented in many conventional mutagenesis strategies. Methods for incorporation of indels in predefined positions in a combinatorial manner have been developed.Although there are some published studies on their use in the directed evolution of biocatalysts,the full potential of these newer methods of gene mutation for enzyme improvement are yet to be demonstrated. [Pg.109]

These investigations also showed that the conversion of ECB to ECB nucleus would proceed more rapidly if ECB were first solubilized in a suitable solvent such as methanol or acetone. However, if the concentration of solvent was too high, the enzyme activity was reduced. Ideally, the enzyme itself could be tailored to suit the industrially preferred conditions (e.g., to make it more resistant to solvent or active at a different pH). One method for achieving this is to use directed evolution [42], whereby genes encoding the enzyme are mutated, screened and then recombined in vitro. Although the contributions of individual amino acid mutations are small, the accumulation of multiple mutations by directed evolution allows significant improvement in the biocatalyst for reactions on substrates or under conditions not already optimized in nature. This approach was used by Arnold and Moore [43] to make a 150-fold improvement in the activity of a -nitrobenzyl esterase in the presence of 15% DMSO. [Pg.240]

In contrast to rational approaches, the directed evolution of enzymes is based on the search of useful functionalities in libraries randomly generated and on improvement by suitable and proper selection. The directed evolution combines two powerful and independent technologies methods for the generation of random genetic libraries and strategies for the selection of variant enzymes with the specific capabilities [499-503]. This process can result in biocatalysts with non-natural proprieties, since the proteins are expressed in recombinant cells decoupled from its biological functions and evolved under unusual conditions. One additional advantage is the possibility to tailor not only individual proteins, but also the whole biosynthetic and catabohc pathways [471]. [Pg.153]

Various techniques are employed to obtain the improved biocatalysts for potential improvement. These include the following mutation and selection, hybridization, protoplast fusion, and recombinant DNA methods. One example of strain improvement is the development of an ethanol-tolerant yeast strain, Saccharomyces 1400, through protoplast fusion of S. distaticus and S. uvarum as reported by D Amore et al. [4]. This yeast strain was used as the biocatalyst by Krishnan et al. [5] for the rapid fermentation of high concentrations of glucose... [Pg.209]

Case studies, biocatalysis vs. heterogeneous catalysis, systematic comparison of overall processes and of catalytic steps, ecological parameters Combination of chemical and biocatalytic steps, toolbox of biocatalysts, back integration Recombinant enzyme, process development, process comparison concerning waste Overview of various production methods, types of biocatalysts... [Pg.7]

Novella IS, Fargues C, GreviUot G (1994) Improvement of extraction of penicillin acylase by a combined use of chemical methods. Biotechnol Bioeng 44 379-382 Ospina S, Lopez-Mungufa A, GonztQez R et al. (1992) Characterization and use of a penicillin acylase biocatalyst. J. Chem Technol Biotechnol 53 205-214 Ospina SS, Merino E, Ramirez OT et til. (1995) Recombinant whole cell penicillin acylase biocatalyst production, characterization and use in the synthesis and hydrolysis of antibiotics. Biotechnol Lett 17 615-620... [Pg.289]

The isolation of recombinant enzymes is generally a rather laborious operation. A rapidly emerging method for large-scale synthesis of complex carbohydrates is the use of metabolically engineered microorganisms. So far three strategies have been used in developing the several whole-cell biocatalysts. [Pg.5]

Another advantage of extremely thermophilic enzymes is that when they are produced recombinantly in mesophilic hosts, heat treatment serves as an efficient method to purify the target enzyme from the host s proteins, which readily denature at higher temperatures (21). This strategy can be used to great advantage for biocatalyst production. [Pg.949]


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See also in sourсe #XX -- [ Pg.376 ]




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