Strain Improvement of Acinetobacter Calcoaceticus D29 for Enhanced Lipase Production by Screening Sodium Citrate Resistant Mutants

2011 ◽  
Vol 343-344 ◽  
pp. 551-555
Author(s):  
Shao Jiong Zhong ◽  
Wei Qi ◽  
Hai Kuan Wang
Keyword(s):  
Sodium Citrate ◽  
Random Mutagenesis ◽  
Strain Improvement ◽  
Acinetobacter Calcoaceticus ◽  
Lipase Production ◽  
Original Strain ◽  
Improvement Program ◽  
Mutant Strains ◽  
General Strain ◽  
Selection For

A strain improvement program was developed to increase lipase production by Acinetobacter calcoaceticus D29, in which mutants were generated by Ultraviolet (UV) radiation and selected by resistance to 1.5% (w/v) sodium citrate. One of the mutant strains UN9 exhibited 48.69% more lipase activity than the original strain did. Although the UV random mutagenesis alone is an effective method for general strain improvement, our results showed that UV mutagenesis combined with selection for sodium citrate resistance is a more efficient strategy for screening mutant strains with enhanced lipase production.

scholarly journals Enhancement of lipase production by ethyl methane sulfonate mutagenesis of soil fungal isolate

2019 ◽  
Vol 6 (sp1) ◽  
pp. 600-606 ◽  
Author(s):  
` Shreya ◽  
Arun Kumar Sharma ◽  
` Ritika ◽  
Nikita Bhati
Keyword(s):  
Wild Strain ◽  
Random Mutagenesis ◽  
Strain Improvement ◽  
Lipase Production ◽  
Maximum Activity ◽  
Spore Suspension ◽  
Ethyl Methane Sulfonate ◽  
Water Control ◽  
Methane Sulfonate ◽  
Ethyl Methane

Strain improvement through random mutagenesis is an extremely developed practice and it plays an important role in the economic growth of microbial agitation processes. The present study comprises of genetic improvement of fungus isolated from petrol pump soil by ethyl methane sulfonate (EMS) mutagenesis for increased production of extracellular lipase. Random mutagenesis was performed by incubating the spore suspension of fungus with EMS at a concentration of 5% (v/v) and 8% (v/v) for 30, 60 and 90 min, respectively. Control set was prepared by incubating the spore suspension with sterile distilled water. Control plate showed maximum number of fungal colonies whereas number of colonies was decreased as we increased exposure time of EMS from 30 to 90 min. The lipase activity of six mutagenic strains and wild strain was determined under submerged fermentation and solid state fermentation. Treated culture named as EMS5%-60min (obtained after 60 min exposure with 5% EMS) exhibited maximum activity (32.09 ± 1.84 IU/ml/min) in SmF as compared to wild strain (8.77 ± 3.52 IU/ml/min) and another treated strain named as EMS8%-90min (obtained after 90 min exposure with 8% EMS) exhibited maximum activity (7.99 ± 0.12 IU/g/min) in SSF as compared to wild strain (1.77 ± 0.71 IU/g/min). The activity of mutagenic strain i.e. EMS5%-60min was increased to 365.90% as compared to 100% activity of wild strain in SmF whereas activity of another mutagenic strain i.e. EMS8%-90min was increased to 451.41% as compared to 100% activity of wild strain in SSF.

Methods of Random Mutagenesis of Aspergillus Strain for Increasing Kojic Acid Production

2021 ◽  
Vol 22 ◽  
Author(s):  
Herman Suryadi ◽  
Marina Ika Irianti ◽  
Tri Hastuti Septiarini
Keyword(s):  
Acid Production ◽  
Kojic Acid ◽  
Ion Beam ◽  
Random Mutagenesis ◽  
Strain Improvement ◽  
Temperature Plasma ◽  
Acid Yield ◽  
Chemical Mutagens ◽  
Kojic Acid Production ◽  
Physical And Chemical

: Kojic acid is an organic acid that is commonly used in the pharmaceutical and cosmetic industries. This acid compound is a secondary metabolite produced by various microorganisms, one of which is Aspergillus oryzae. Typically, improving the strain can enhance kojic acid production. A mutation is one of the tools to perform strain improvement because the change in kojic acid-producing genes effectively increases kojic acid yield. Random mutagenesis is a classic approach for inducing and producing mutants with random mutations. The mutagenesis can be generated by the individual physical and chemical mutagen, combined physical and chemical mutagens, or initiate by protoplast preparation. Aspergillus strains that are exposed to physical mutagens (e.g., UV) or chemical mutagens (e.g., N-methyl-N-nitro-N-nitrosoguanidine (NTG)) showed their abilities in increasing kojic acid production. Several new mutation methods, such as Ion Beam Implantation and Atmospheric and room temperature plasma (ARTP), also showed good responses in enhancing the production of biological products such as kojic acid. This review compared different random mutagenesis methods of Aspergillus strain with various mutagen types to provide better insight for researchers in choosing the most suitable method to increase kojic acid production.

scholarly journals Random Mutagenesis of Filamentous Fungi Strains for High-Yield Production of Secondary Metabolites: The Role of Polyamines

2020 ◽  
Author(s):  
Alexander A. Zhgun
Keyword(s):  
Filamentous Fungi ◽  
Random Mutagenesis ◽  
Strain Improvement ◽  
Main Tool ◽  
High Yield ◽  
Individual Species ◽  
Airborne Spores ◽  
Yield Production ◽  
Improvement Programs ◽  
The Individual

A filamentous fungus (also called molds or moldy fungus) is a taxonomically diverse organism from phylum Zygomycota and Ascomycota with filamentous hyphae and has the ability to produce airborne spores or conidia. Currently, more than 70,000 molds are known, and some of them contain unique and unusual biochemical pathways. A number of products from such pathways, especially, the secondary metabolite (SM) pathways are used as important pharmaceuticals, including antibiotics, statins, and immunodepresants. Under different conditions, the individual species can produce more than 100 SM. The strain improvement programs lead to high yielding in target SM and significant reduction of spin-off products. The main tool for the strain improvement of filamentous fungi is random mutagenesis and screening. The majority of industrial overproducing SM strains were developed with the help of such technique over the past 50–70 years; the yield of the target SM increased by 100- to 1000-fold or more. Moreover, most of the strains have reached their technological limit of improvement. A new round of mutagenesis has not increased overproduction. Recently, it was shown that that the addition of exogenous polyamines may increase the production of such improved strains of filamentous fungi. The possible molecular mechanism of this phenomenon and its biotechnological applications are discussed.

scholarly journals Mutagenesis development of actinoplanes sp. KCTC 9161 by N-methyl-N'-nitro-N-nitrosoguanidine (NTG) and screening for acarbose production

2018 ◽  
Vol 14 (4) ◽  
pp. 753-760
Author(s):  
Do Thi Tuyen ◽  
Nguyen The Duong ◽  
Le Thanh Hoang
Keyword(s):  
Type Ii Diabetes ◽  
Wild Type Strain ◽  
Fermentation Medium ◽  
Original Strain ◽  
Wild Type ◽  
Chromatography Method ◽  
Mutant Strains ◽  
Insulin Dependent ◽  
Mutant Lines ◽  
Layer Chromatography

Acarbose has been widely used in the therapy of type II diabetes (non-insulin dependent) because it controls blood sugar contents of patients after meals. Acarbose, a pseudo-oligosaccharide, acts as a competitive -glucosidase inhibitor. Acarbose is produced by the strains of Bacillus, Streptomyces and Actinoplanes sp. The aim of this study was to develop mutagenesis for an Actinoplanes sp. strain and screening for acarbose production. The spores of Actinoplanes sp. KCTC 9161 strain were subjected to be mutated by N-methyl-N'-nitro-N-nitrosoguanidine (NTG) for screening and finding mutant strains that were capable of production of higher acarbose (an inhibitor of α-glucosidase) higher than wild type strain. Firstly, the original NTG solution was prepared in phosphate buffer 0.05 M, pH 6.9 and the safety concentration of NTG was determined at 5 mg/ml. Then, the spores were incubated with different NTG amounts and duration. The living colonies were transferred to fermentation medium. The results obtained showed that 15 mutant strains were produced higher acarbose than wild type when used thin layer chromatography method for analysis and comparing with standard acarbose (Sigma). Three cell lines among total tested 15 mutant lines of Actinoplanes sp. KCTC 9161 produced acarbose at a higher level or indicated a higher inhibitory activity toward α-glucosidase than the original strain. Enzymatic inhibitory ativity of α-glucosidase of three mutant strains (Actinoplanes sp. KCTC- L4, L11, L14) was increased 1.3 fold higher than wild type and Actinoplanes sp. KCTC spores were very sensitive to NTG toxic, 98% spores could not survive at the treatment condition of 50 µg NTG for 30 minutes. In addition, an applicable protocol for mutating Actinoplanes sp. using NTG was suggested for further research.

Mandelate Dehydrogenase with Altered Stereospecificity in Mutant Strains of Acinetobacter calcoaceticus N.C.I.B. 8250

1976 ◽  
Vol 4 (4) ◽  
pp. 614-615 ◽  
Author(s):  
C. A. FEWSON ◽  
JEAN D. BEGGS ◽  
ELLEN SEENAN ◽  
E. F. AHLQUIST
Keyword(s):  
Acinetobacter Calcoaceticus ◽  
Mutant Strains

Molecular Cloning of the gyrA andgyrB Genes of Bacteroides fragilis Encoding DNA Gyrase

1999 ◽  
Vol 43 (10) ◽  
pp. 2423-2429 ◽  
Author(s):  
Yoshikuni Onodera ◽  
Kenichi Sato
Keyword(s):  
Hot Spot ◽  
Bacteroides Fragilis ◽  
Dna Gyrase ◽  
E Coli ◽  
Important Target ◽  
Mutant Strains ◽  
Genes Encoding ◽  
Gyrase A ◽  
Selection For

ABSTRACT The genes encoding the DNA gyrase A and B subunits ofBacteroides fragilis were cloned and sequenced. ThegyrA and gyrB genes code for proteins of 845 and 653 amino acids, respectively. These proteins were expressed inEscherichia coli, and the combination of GyrA and GyrB exhibited ATP-dependent supercoiling activity. To analyze the role of DNA gyrase in quinolone resistance of B. fragilis, we isolated mutant strains by stepwise selection for resistance to increasing concentrations of levofloxacin. We analyzed the resistant mutants and showed that Ser-82 of GyrA, equivalent to resistance hot spot Ser-83 of GyrA in E. coli, was in each case replaced with Phe. These results suggest that DNA gyrase is an important target for quinolones in B. fragilis.

scholarly journals Two Components of a velvet-Like Complex Control Hyphal Morphogenesis, Conidiophore Development, and Penicillin Biosynthesis in Penicillium chrysogenum

2010 ◽  
Vol 9 (8) ◽  
pp. 1236-1250 ◽  
Author(s):  
Birgit Hoff ◽  
Jens Kamerewerd ◽  
Claudia Sigl ◽  
Rudolf Mitterbauer ◽  
Ivo Zadra ◽  
...  
Keyword(s):  
Penicillium Chrysogenum ◽  
High Performance ◽  
Strain Improvement ◽  
Bimolecular Fluorescence Complementation ◽  
Northern Hybridization ◽  
Penicillin Biosynthesis ◽  
Improvement Program ◽  
Content Type ◽  
Pellet Formation ◽  
Severe Impairment

ABSTRACT Penicillium chrysogenum is the industrial producer of the antibiotic penicillin, whose biosynthetic regulation is barely understood. Here, we provide a functional analysis of two major homologues of the velvet complex in P. chrysogenum, which we have named P. chrysogenum velA (PcvelA) and PclaeA. Data from array analysis using a ΔPcvelA deletion strain indicate a significant role of PcVelA on the expression of biosynthesis and developmental genes, including PclaeA. Northern hybridization and high-performance liquid chromatography quantifications of penicillin titers clearly show that both PcVelA and PcLaeA play a major role in penicillin biosynthesis in a producer strain that underwent several rounds of UV mutagenesis during a strain improvement program. Both regulators are further involved in different developmental processes. While PcvelA deletion leads to light-independent conidial formation, dichotomous branching of hyphae, and pellet formation in shaking cultures, a ΔPclaeA strain shows a severe impairment in conidiophore formation under both light and dark conditions. Bimolecular fluorescence complementation assays provide evidence for a velvet-like complex in P. chrysogenum, with structurally conserved components that have distinct developmental roles, illustrating the functional plasticity of these regulators in genera other than Aspergillus.

Phosphorylation of Adenosine and Deoxyadenosine in Ehrlich Ascites Carcinoma Cells Resistant to 6-(Methylmercapto)purine Ribonucleoside

1972 ◽  
Vol 50 (4) ◽  
pp. 423-427 ◽  
Author(s):  
Christopher A. Lomax ◽  
J. Frank Henderson
Keyword(s):  
Mutant Cell ◽  
Ehrlich Ascites Carcinoma ◽  
Adenosine Kinase ◽  
Carcinoma Cells ◽  
Ehrlich Ascites Tumor Cells ◽  
Nucleotide Synthesis ◽  
Ehrlich Ascites ◽  
Mutant Strains ◽  
Selection For ◽  
Reduced Activity

The metabolism of adenosine and deoxyadenosine has been studied in Ehrlich ascites tumor cells and in a subline (EAC-R2) resistant to growth inhibition by 6-(methylmercapto)purine ribonucleoside (6MeMPR). The mutant cell line showed reduced rates of conversion of adenosine and deoxyadenosine into nucleotides. It was concluded from this that both compounds probably are phosphorylated by adenosine kinase. Comparison of the rates of nucleotide synthesis at increasing concentrations of adenosine indicated differences in the Km and Vmax values of the adenosine kinases in the parent and mutant strains. Competition experiments between adenosine and 6MeMPR showed that adenosine kinase in EAC-R2 had probably lost all affinity for the analogue. Selection for resistance to 6MeMPR therefore seems to have altered the structure of adenosine kinase, such that it has no activity with 6MeMPR and reduced activity with adenosine and deoxyadenosine.

Mutant alleles of the essential 14-3-3 gene in Candida albicans distinguish between growth and filamentation

Microbiology ◽  
2004 ◽  
Vol 150 (6) ◽  
pp. 1911-1924 ◽  
Author(s):  
Glen E. Palmer ◽  
Kevin J. Johnson ◽  
Sumana Ghosh ◽  
Joy Sturtevant
Keyword(s):  
Candida Albicans ◽  
Random Mutagenesis ◽  
Optimal Growth ◽  
Temperature Sensitive ◽  
Nucleotide Substitutions ◽  
Nutrient Sources ◽  
Cellular Processes ◽  
Mutant Strains ◽  
Opportunistic Fungal Pathogen ◽  
The Individual

The opportunistic fungal pathogen Candida albicans has the ability to exploit diverse host environments and can either reside commensally or cause disease. In order to adapt to its new environment it must respond to new physical conditions, nutrient sources, and the host immune response. This requires the co-regulation of multiple signalling networks. The 14-3-3 family of proteins is highly conserved in all eukaryotic species. These proteins regulate signalling pathways involved in cell survival, the cell cycle, and differentiation, and effect their functions via interactions with phosphorylated serines/threonines. In C. albicans there is only one 14-3-3 protein, Bmh1p, and it is required for vegetative growth and optimal filamentation. In order to dissect separate functions of Bmh1p in C. albicans, site-directed nucleotide substitutions were made in the C. albicans BMH1 gene based on studies in other species. Putative temperature-sensitive, ligand-binding and dimerization mutants were constructed. In addition two mutant strains identified through random mutagenesis were analysed. All five mutant strains demonstrated varying defects in growth and filamentation. This paper begins to segregate functions of Bmh1p that are required for optimal growth and the different filamentation pathways. These mutant strains will allow the identification of 14-3-3 target interactions and correlate the individual functions of Bmh1p to cellular processes involved in pathogenesis.

scholarly journals Rapid Evolution of Novel Traits in Microorganisms

2001 ◽  
Vol 67 (8) ◽  
pp. 3645-3649 ◽  
Author(s):  
Olga Selifonova ◽  
Fernando Valle ◽  
Volker Schellenberger
Keyword(s):  
Mutation Rate ◽  
Complex Traits ◽  
Rapid Evolution ◽  
Random Mutagenesis ◽  
Strain Improvement ◽  
Temperature Sensitive ◽  
Bacterial Strains ◽  
Mutator Strains ◽  
High Concentrations

ABSTRACT The use of natural microorganisms in biotransformations is frequently constrained by their limited tolerance to the high concentrations of metabolites and solvents required for effective industrial production. In many cases, more robust strains have to be generated by random mutagenesis and selection. This process of directed evolution can be accelerated in mutator strains, which carry defects in one or more of their DNA repair genes. However, in order to use mutator strains, it is essential to restore the normal low mutation rate of the selected organisms immediately after selection to prevent the accumulation of undesirable spontaneous mutations. To enable this process, we constructed temperature-sensitive plasmids that temporarily increase the mutation frequency of their hosts by 20- to 4,000-fold. Under appropriate selection pressure, microorganisms transformed with mutator plasmids can be quickly evolved to exhibit new, complex traits. By using this approach, we were able to increase the tolerance of three bacterial strains to dimethylformamide by 10 to 20 g/liter during only two subsequent transfers. Subsequently, the evolved strains were returned to their normal low mutation rate by curing the cells of the mutator plasmids. Our results demonstrate a new and efficient method for rapid strain improvement based on in vivo mutagenesis.

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