Industrial strain improvement: Mutagenesis and random screening procedures

Rowlands, Robert T.

doi:10.1016/0141-0229(84)90070-x

Cited by 142 publications

(65 citation statements)

References 45 publications

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“…The process of mutagenesis and rational selection has been utilized for improvement of industrially important strains for overproduction of desired metabolites [19,20,37]. In our previous study, an ethyl methane sulfonate (EMS) induced (exposure at 20 ll ml -1 for 30 min with 92 % reduction in viability), atorvastatin (20 lg ml -1 ) tolerating mutant EA22 was generated from S. johnsonii ATCC-20490 with 2-fold improvement in CoQ 10 titer (HPTLC method) [17].…”

Section: Mutagenesis Selection Of Mutants and Screening In Shake Flaskmentioning

confidence: 99%

“…During strain improvement program on this strain, the improved mutant strain EA22 was previously generated by EMS mutagenesis followed by rational selection [19] on atorvastatin (20 lg ml -1 ) [17]. Re-mutagenesis process brings about improvement in yields [20]; hence we continued our efforts on this strain to bring significant improvement in CoQ 10 content by induced re-mutagenesis and rational selection.…”

Section: Introductionmentioning

confidence: 99%

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Morphological and Molecular Differentiation of Sporidiobolus johnsonii ATCC 20490 and Its Coenzyme Q10 Overproducing Mutant Strain UF16

et al. 2014

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Coenzyme Q 10 (CoQ 10 ) is an industrially important molecule having nutraceutical and cosmeceutical applications. CoQ 10 is mainly produced by microbial fermentation and the process demands the use of strains with high productivity and yields of CoQ 10 . During strain improvement program consisting of sequential induced mutagenesis, rational selection and screening process, a mutant strain UF16 was generated from Sporidiobolus johnsonii ATCC 20490 with 2.3-fold improvements in CoQ 10 content. EMS and UV rays were used as mutagenic agents for generating UF16 and it was rationally selected based on atorvastatin resistance as well as survival at free radicals exposure. We investigated the genotypic and phenotypic changes in UF16 in order to differentiate it from wild type strain. Morphologically it was distinct due to reduced pigmentation of colony, reduced cell size and significant reduction in mycelial growth forms with abundance of yeast forms. At molecular level, UF16 was differentiated based on PCR fingerprinting method of RAPD as well as large and small-subunit rRNA gene sequences.Rapid molecular technique of RAPD analysis using six primers showed 34 % polymorphic fragments with mean genetic distance of 0.235. The partial sequences of rRNAgene revealed few mutation sites on nucleotide base pairs. However, the mutations detected on rRNA gene of UF16 were less than 1 % of total base pairs and its sequence showed 99 % homology with the wild type strain. These mutations in UF16 could not be linked to phenotypic or genotypic changes on CoQ 10 biosynthetic pathway that resulted in improved yield. Hence, investigating the mutations responsible for deregulation of CoQ 10 pathway is essential to understand the cause of overproduction in UF16. Phylogenetic analysis based on RAPD bands and rRNA gene sequences coupled with morphological variations, exhibited the novelty of mutant UF16 having potential for improved CoQ 10 production.

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Section: Mutagenesis Selection Of Mutants and Screening In Shake Flaskmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Morphological and Molecular Differentiation of Sporidiobolus johnsonii ATCC 20490 and Its Coenzyme Q10 Overproducing Mutant Strain UF16

et al. 2014

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“…Strains producing metabolites in excess of 50 g/L (penicillin) (11) and other secondary metabolites in titers as high as 80 g/L is reported in the literature (9,12). Zymomonas mobilis strains overproduc-ing fructose polymer, levan, at titers as high as 20 g/L in 24 h have been isolated by NTG mutagenesis followed by selections (13).…”

Section: Classical Strain Engineering Methodologymentioning

confidence: 99%

Engineering Complex Phenotypes in Industrial Strains

Patnaik

2008

Biotechnol. Prog.

102

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The global demand is rising for greener manufacturing processes that are cost-competitive and available in a timely manner. This has led to the development of a series of new tools and integrative platforms enabling rapid engineering of complex phenotypes in industrial microbes. By blending "old classical methods" of strain isolation with "newer approaches" of cell engineering, researchers are demonstrating the ability to stack multiple complex phenotypes in industrial hosts with some level of certainty. Newer tools for dissecting the genotype-phenotype correlation include association analysis (Precision Engineering), multiSCale Analysis of Library Enrichment (SCALE) in competition experiments, whole-genome transcriptional analysis, and proteomics and metabolomics technology. These newer and older tools of metabolic engineering and synthetic biology when combined with recent whole cell engineering approaches like whole genome shuffling, global transciptome machinery engineering, and directed evolutionary engineering, provide a powerful platform for engineering complex phenotypes in industrial strains. This review attempts to highlight and compare these newer tools and approaches with traditional strain isolation procedures as it applies to genome engineering with examples taken from literature.

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“…Although recently developed rational approaches based on Omics-driven genetic engineering have been applied to various commercially valuable microbial systems [13,19,7,6], traditional random mutagenesis [1,26] is still routinely used, especially for strains with little available genetic information or that are recalcitrant to genetic manipulation [17,23]. Thus, both traditional and rational strain improvement approaches are equally important and should be well-balanced to achieve maximum metabolite productivity.…”

mentioning

confidence: 99%

“…gene, VHb, as a model system. The VHb gene is a hemoglobin-like gene present in the chromosome of the aerobic Gram-negative bacterium, Vitreoscilla sp., whose protein plays an important role in oxygen transfer [11,17,22,25]. Heterologous expressions of the VHb gene in several microorganisms, including E. coli, stimulates ATP generation by promoting efficient oxygen transfer in an oxygen-limited environment, leading to enhanced cell growth and protein synthesis [2,5,14,15,27].…”

mentioning

confidence: 99%