Improvement of microbial strains and fermentation processes

Parekh, Sarad R.; Vinci, Victor A.; Strobel, Robert J.

doi:10.1007/s002530000403

Cited by 432 publications

(264 citation statements)

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“…These classical strain improvement methods have historical use. Hence, strains derived from non-recombinant methods or classical strain improvement are widely accepted as less significant process changes, assuming that product specifications are met and regulatory notification is completed (Parekh et al 2000).…”

Section: Introductionmentioning

confidence: 99%

“…Induced mutations are achieved by subjecting the genetic material to physical or chemical agents called mutagens. Conventional mutagens employed for strain improvement include N-methyl-N′-nitro-N-nitrosoguanidine (NTG), ethyl methanesulfonate (EMS), hydroxylamine (NH 2 OH), nitrous acid (HNO 2 ) and ultraviolet rays (UV) (Demain and Adrio 2008;Parekh et al 2000). Each mutagen causes DNA alterations in a specific manner.…”

Section: Introductionmentioning

confidence: 99%

“…Most mutagenic agents cause some damage to the DNA through deletion, addition, transversion or substitution of bases or breakage of DNA strands. For example, mutation by UV irradiation induces pyrimidine dimerization and cross-links in DNA (Parekh et al 2000).…”

Section: Introductionmentioning

confidence: 99%

“…Screening strategies may be divided into two basic types: (a) the non-selective random screening, where randomly picked isolates are tested for desired qualities; and (b) rationalized selection, based on some form of pre-selection (Parekh et al 2000).…”

Section: Introductionmentioning

confidence: 99%

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Microbial strain improvement for enhanced polygalacturonase production by Aspergillus sojae

Heerd

Tarı

Fernández‐Lahore

2014

Appl Microbiol Biotechnol

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Strain improvement is a powerful tool in commercial development of microbial fermentation processes. Strains of Aspergillus sojae which were previously identified as polygalacturonase producers were subjected to the costeffective mutagenesis and selection method, the so-called random screening. Physical (ultraviolet irradiation at 254 nm) and chemical mutagens (N-methyl-N′-nitro-Nnitrosoguanidine) were used in the development and implementation of a classical mutation and selection strategy for the improved production of pectic acid-degrading enzymes. Three mutation cycles of both mutagenic treatments and also the combination of them were performed to generate mutants descending from A. sojae ATCC 20235 and mutants of A. sojae CBS 100928. Pectinolytic enzyme production of the mutants was compared to their wild types in submerged and solid-state fermentation. Comparing both strains, higher pectinase activity was obtained by A. sojae ATCC 20235 and mutants thereof. The highest polygalacturonase activity (1,087.2±151.9 U/g) in solid-state culture was obtained by mutant M3, which was 1.7 times increased in comparison to the wild strain, A. sojae ATCC 20235. Additional, further mutation of mutant M3 for two more cycles of treatment by UV irradiation generated mutant DH56 with the highest polygalacturonase activity (98.8±8.7 U/mL) in submerged culture. This corresponded to 2.4-fold enhanced polygalacturonase production in comparison to the wild strain. The results of this study indicated the development of a classical mutation and selection strategy as a promising tool to improve pectinolytic enzyme production by both fungal strains.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Microbial strain improvement for enhanced polygalacturonase production by Aspergillus sojae

Heerd

Tarı

Fernández‐Lahore

2014

Appl Microbiol Biotechnol

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“…There have been extensive reviews regarding the application of random mutagenesis and directed evolution for novel development or enhancement of existing microbial cell factories for the production of a wide range of industrial biotechnology products (Demain, 2000;Demain and Adrio, 2008a,b;Parekh et al, 2000;Patnaik, 2008;Schmeisser et al, 2007). What is often referred to as ''classical strain development'' is dependent on the capability of inducing and promoting genetic diversity, under controlled laboratory conditions, in a desirable production host organism that can be selectively screened, isolated, cultured, and preserved based on a phenotypic criteria.…”

Section: Engineering Microbial Metabolismmentioning

confidence: 99%

Industrial systems biology

Otero

Nielsen

2009

Biotech & Bioengineering

134

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ABSTRACT:The chemical industry is currently undergoing a dramatic change driven by demand for developing more sustainable processes for the production of fuels, chemicals, and materials. In biotechnological processes different microorganisms can be exploited, and the large diversity of metabolic reactions represents a rich repository for the design of chemical conversion processes that lead to efficient production of desirable products. However, often microorganisms that produce a desirable product, either naturally or because they have been engineered through insertion of heterologous pathways, have low yields and productivities, and in order to establish an economically viable process it is necessary to improve the performance of the microorganism. Here metabolic engineering is the enabling technology. Through metabolic engineering the metabolic landscape of the microorganism is engineered such that there is an efficient conversion of the raw material, typically glucose, to the product of interest. This process may involve both insertion of new enzymes activities, deletion of existing enzyme activities, but often also deregulation of existing regulatory structures operating in the cell. In order to rapidly identify the optimal metabolic engineering strategy the industry is to an increasing extent looking into the use of tools from systems biology. This involves both x-ome technologies such as transcriptome, proteome, metabolome, and fluxome analysis, and advanced mathematical modeling tools such as genome-scale metabolic modeling. Here we look into the history of these different techniques and review how they find application in industrial biotechnology, which will lead to what we here define as industrial systems biology.

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Fermentation

Junker

2004

Kirk-Othmer Encyclopedia of Chemical Technology

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Fermentation processes, products, and economic aspects are summarized according to the product classes of primary metabolites, secondary metabolites, biomass, enzymes (and whole cell biocatalysts), and biologicals. Although the information is focused on aerobic stirred tank processes, anaerobic, bubble column, and/or immobilized production techniques are referenced where applicable. Advantages of biochemical production over strictly synthetic processes are discussed. The history of fermentation is described at time periods of pre‐1700s, 1700s–1900, 1900–1945, 1945–1960, 1960–1970, 1970–1995, and 1995 to the present. This progression is followed by an overview of microbiological and fermentation principles, equipment requirements, inoculum development and scale‐up techniques, utilities, and regulatory considerations. Throughout this article specific product and process examples are included.

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Improvement of microbial strains and fermentation processes

Cited by 432 publications

References 0 publications

Microbial strain improvement for enhanced polygalacturonase production by Aspergillus sojae

Microbial strain improvement for enhanced polygalacturonase production by Aspergillus sojae

Industrial systems biology

Fermentation

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