scholarly journals Biocatalytic Ketone Reduction - A Study on Screening and Effect of Culture Conditions on the Reduction of Selected Ketones

2013 ◽  
Vol 6 ◽  
pp. 54-77
Author(s):  
Ramprasad Kuncham ◽  
K.T. Gurumurthy ◽  
N. Chandan ◽  
Aamir Javed ◽  
L.S. Ashwini ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Aspergillus Flavus ◽  
Incubation Temperature ◽  
Carbon Sources ◽  
Nitrogen Sources ◽  
Good Alternative ◽  
Culture Conditions ◽  
Maximum Effect ◽  
Enzyme Expression ◽  
Maximum Conversion

Microbial conversions are gaining importance in the synthesis of important drug metabolites and their intermediates as they are good alternative to chemical synthesis since they are enantio-selective and regio-selective and even can be carried out at ambient temperature and atmospheric pressure. Till date, biocatalytic reduction of acetophenone and its derivatives has been widely reported. In the present study, we have made an attempt to carry out the microbial bioreduction of o-hydroxyacetophenone by screening some of the selected microorganisms which were obtained from culture collection centre as well as those which are isolated in our Microbiology lab. The selected microorganisms include Aspergillus ochraceous, Aspergillus flavus, Aspergillus tubingenesis, Aspergillus niger, Rhizopus stolanifer MTCC 162, Rhizopus stolanifer MTCC 2591 and Baker’s yeast.Among the seven microorganisms screened for the bioreduction of o-hydroxyacetophenone, Baker’s yeast and Aspergillus tubingenesis showed significant bioconversion where as Aspergillus ochraceous exhibited the least bioconversion.In our earlier study it was found that Aspergillus flavus has the required bioreductase enzyme, which showed the maximum conversion of p-chloroacetophenone to p-chlorophenylethanol. Hence optimization of culture conditions to get maximum enzyme expression and hence maximum conversion was thought off. The parameters considered for the study include effect of various Carbon sources, Nitrogen source, Metal ions, incubation Temperature and media pH on enzyme expression. The optimized culture a condition at which maximum bioconversion was achieved was maltose among various carbon sources. Tryptone was found to have maximum effect among the nitrogen sources. Media pH 7.6 and incubation temperature of 35 °C was found to be favourable for maximum enzyme activity. Among various divalent metal salts, addition of magnesium sulphate to the media significantly increased the enzyme activity.

scholarly journals Putative metabolic pathway for the bioproduction of bikaverin and intermediates thereof in the wild Fusarium oxysporum LCP531 strain

AMB Express ◽  
2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Juliana Lebeau ◽  
Thomas Petit ◽  
Laurent Dufossé ◽  
Yanis Caro
Keyword(s):  
Metabolic Pathway ◽  
Carbon Sources ◽  
Nitrogen Sources ◽  
Pharmaceutical Products ◽  
Culture Conditions ◽  
Fusarium Fujikuroi ◽  
Submerged Cultures ◽  
In The Wild ◽  
Considerable Work ◽  
Pharmaceutical Uses

AbstractFungal naphthoquinones, like red bikaverin, are of interest due to their growing applications in designing pharmaceutical products. Though considerable work has been done on the elucidation of bikaverin biosynthesis pathway in Fusarium fujikuroi, very few reports are available regarding its bioproduction in F. oxysporum. We are hereby proposing a putative metabolic pathway for bikaverin bioproduction in a wild F. oxysporum strain by cross-linking the pigment profiles we obtained under two different fermentation conditions with literature. Naphthoquinone pigments were extracted with a pressurized liquid extraction method, and characterized by HPLC–DAD and UHPLC-HRMS. The results led to the conclusions that the F. oxysporum LCP531 strain was able to produce bikaverin and its various intermediates, e.g., pre-bikaverin, oxo-pre-bikaverin, dinor-bikaverin, me-oxo-pre-bikaverin, and nor-bikaverin, in submerged cultures in various proportions. To our knowledge, this is the first report of the isolation of these five bikaverin intermediates from F. oxysporum cultures, providing us with steady clues for confirming a bikaverin metabolic pathway as well as some of its regulatory patterns in the F. oxysporum LCP531 strain, based on the previously reported model in F. fujikuroi. Interestingly, norbikaverin accumulated along with bikaverin in mycelial cells when the strain grew on simple carbon and nitrogen sources and additional cofactors. Along bikaverin production, we were able to describe the excretion of the toxin beauvericin as main extrolite exclusively in liquid medium containing complex nitrogen and carbon sources, as well as the isolation of ergosterol derivate in mycelial extracts, which have potential for pharmaceutical uses. Therefore, culture conditions were also concluded to trigger some specific biosynthetic route favoring various metabolites of interest. Such observation is of great significance for selective production of pigments and/or prevention of occurrence of others (aka mycotoxins).

scholarly journals β-Fructofuranosidase andβ–D-Fructosyltransferase from NewAspergillus carbonariusPC-4 Strain Isolated from Canned Peach Syrup: Effect of Carbon and Nitrogen Sources on Enzyme Production

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Gustavo Carvalho do Nascimento ◽  
Ryhára Dias Batista ◽  
Claudia Cristina Auler do Amaral Santos ◽  
Ezequiel Marcelino da Silva ◽  
Fabrício Coutinho de Paula ◽  
...  
Keyword(s):  
Yeast Extract ◽  
Soybean Protein ◽  
Low Cost ◽  
Carbon Sources ◽  
Nitrogen Sources ◽  
Culture Conditions ◽  
Carbon And Nitrogen ◽  
Production Values ◽  
Pure Carbon ◽  
Fermentation Parameters

β-fructofuranosidase (invertase) andβ-D-fructosyltransferase (FTase) are enzymes used in industrial processes to hydrolyze sucrose aiming to produce inverted sugar syrup or fructooligosaccharides. In this work, a blackAspergillussp. PC-4 was selected among six filamentous fungi isolated from canned peach syrup which were initially screened for invertase production. Cultivations with pure carbon sources showed that invertase and FTase were produced from glucose and sucrose, but high levels were also obtained from raffinose and inulin. Pineapple crown was the best complex carbon source for invertase (6.71 U/mL after 3 days of cultivation) and FTase production (14.60 U/mL after 5 days of cultivation). Yeast extract and ammonium chloride nitrogen sources provided higher production of invertase (6.80 U/mL and 6.30 U/mL, respectively), whereas ammonium nitrate and soybean protein were the best nitrogen sources for FTase production (24.00 U/mL and 24.90 U/mL, respectively). Fermentation parameters for invertase using yeast extract wereYP/S= 536.85 U/g andPP= 1.49 U/g/h. FTase production showed values ofYP/S= 2,627.93 U/g andPP= 4.4 U/h using soybean protein. The screening for best culture conditions showed an increase of invertase production values by 5.10-fold after 96 h cultivation compared to initial experiments (fungi bioprospection), while FTase production increased by 14.60-fold (44.40 U/mL) after 168 h cultivation.A. carbonariusPC-4 is a new promising strain for invertase and FTase production from low cost carbon sources, whose synthesized enzymes are suitable for the production of inverted sugar, fructose syrups, and fructooligosaccharides.

scholarly journals Global Survey of Canonical Aspergillus flavus G Protein-Coupled Receptors

mBio ◽  
2014 ◽  
Vol 5 (5) ◽  
Author(s):  
Katharyn J. Affeldt ◽  
Joseph Carrig ◽  
Meareg Amare ◽  
Nancy P. Keller
Keyword(s):  
G Protein ◽  
Aspergillus Flavus ◽  
Effective Means ◽  
Carbon Sources ◽  
Nitrogen Sources ◽  
G Protein Coupled Receptors ◽  
Food Sources ◽  
Economic Losses ◽  
Content Type ◽  
G Protein Coupled

ABSTRACTG protein-coupled receptors (GPCRs) are transmembrane receptors that relay signals from the external environment inside the cell, allowing an organism to adapt to its surroundings. They are known to detect a vast array of ligands, including sugars, amino acids, pheromone peptides, nitrogen sources, oxylipins, and light. Despite their prevalence in fungal genomes, very little is known about the functions of filamentous fungal GPCRs. Here we present the first full-genome assessment of fungal GPCRs through characterization of null mutants of all 15 GPCRs encoded by the aflatoxin-producing fungusAspergillus flavus. All strains were assessed for growth, development, ability to produce aflatoxin, and response to carbon sources, nitrogen sources, stress agents, and lipids. Most GPCR mutants were aberrant in one or more response processes, possibly indicative of cross talk in downstream signaling pathways. Interestingly, the biological defects of the mutants did not correspond with assignment to established GPCR classes; this is likely due to the paucity of data for characterized fungal GPCRs. Many of the GPCR transcripts were differentially regulated under various conditions as well. The data presented here provide an extensive overview of the full set of GPCRs encoded byA. flavusand provide a framework for analysis in other fungal species.IMPORTANCEAspergillus flavusis an opportunistic pathogen of crops and animals, including humans, and it produces a carcinogenic toxin called aflatoxin. Because of this,A. flavusaccounts for food shortages and economic losses in addition to sickness and death. Effective means of combating this pathogen are needed to mitigate its deleterious effects. G protein-coupled receptors (GPCRs) are often used as therapeutic targets due to their signal specificity, and it is estimated that half of all drugs target GPCRs. In fungi such asA. flavus, GPCRs are likely necessary for sensing the changes in the environment, including food sources, developmental signals, stress agents, and signals from other organisms. Therefore, elucidating their functions inA. flavuscould identify ideal receptors against which to develop antagonists.

scholarly journals A Novel Promising Strain ofTrichoderma evansii(WF-3) for Extracellularα-Galactosidase Production by Utilizing Different Carbon Sources under Optimized Culture Conditions

2014 ◽  
Vol 2014 ◽  
pp. 1-12
Author(s):  
Aishwarya Chauhan ◽  
Nikhat Jamal Siddiqi ◽  
Bechan Sharma
Keyword(s):  
Enzyme Activity ◽  
Wheat Straw ◽  
Guar Gum ◽  
Carbon Sources ◽  
Culture Conditions ◽  
Enzyme Synthesis ◽  
Basic Medium ◽  
Growth Media ◽  
Bean Meal ◽  
Soya Bean Meal

A potential fungal strain ofTrichodermasp. (WF-3) was isolated and selected for the production ofα-galactosidase. Optimum conditions for mycelial growth and enzyme induction were determined. Basal media selected for the growth of fungal isolate containing different carbon sources like guar gum (GG), soya bean meal (SM), and wheat straw (WS) and combinations of these carbon substrates with basic sugars like galactose and sucrose were used to monitor their effects onα-galactosidase production. The results of this study indicated that galactose and sucrose enhanced the enzyme activity in guar gum (GG) and wheat straw (WS). Maximumα-galactosidase production (213.63 UmL−1) was obtained when the basic medium containing GG is supplemented with galactose (5 mg/mL). However, the presence of galactose and sucrose alone in the growth media shows no effect. Soya meal alone was able to supportT. evansiito produce maximum enzyme activity (170.36 UmL−1). The incubation time, temperature, and pH for the maximum enzyme synthesis were found to be 120 h (5 days), 28°C, and 4.5–5.5, respectively. All the carbon sources tested exhibited maximum enzyme production at 10 mg/mL concentration. Among the metal ions tested, Hg was found to be the strongest inhibitor of the enzyme. Among the chelators, EDTA acted as stronger inhibitor than succinic acid.

scholarly journals Production of Xylanase from Arthrobacter sp. MTCC 6915 Using Saw Dust As Substrate under Solid State Fermentation

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Sevanan Murugan ◽  
Donna Arnold ◽  
Uma Devi Pongiya ◽  
P.M. Narayanan
Keyword(s):  
Enzyme Activity ◽  
Solid State ◽  
Incubation Temperature ◽  
Nitrogen Sources ◽  
Optimal Temperature ◽  
Carbon And Nitrogen Sources ◽  
Xylanase Production ◽  
Carbon And Nitrogen ◽  
Saw Dust ◽  
Production Temperature

Saw dust was used as substrate for xylanase production from Arthrobacter sp. MTCC 6915. The study of period of incubation, temperature, pH, carbon, and nitrogen sources for xylanase production was optimized. Xylanase production was found to be optimum at an incubation period of 96 hrs (117.0 U/mL), temperature 30°C (105.0 U/mL), and pH 9.0 (102.9 U/mL). The results showed that the xylanase production was found to be higher in the presence of carboxymethylcellulose (176.4 U/mL) and dextrose (126.0 U/mL). It was also observed that peptone (170.1 U/mL) and beef extract (161.7 U/mL) supported maximum xylanase production.The enzyme was characterized and found to be fairly active at pH 9 (764.4 U/mL) and temperature 60°C (819 U/mL). Even in the present study, a major difference in the production temperature (30°C) and optimal temperature (60°C) of the enzyme activity was observed. However, the pH of the production media and the enzyme activity were found to be the same (pH 9).

scholarly journals Cultivation of micro-algae for Production of Biodiesel: An optimized Process

2016 ◽  
Vol 7 ◽  
Author(s):  
Abebe Girma Demissie ◽  
Bhaskarrao Chinthapalli ◽  
Shumet Tenaw ◽  
D. S. Vijaya Chitra
Keyword(s):  
Algal Biomass ◽  
Incubation Temperature ◽  
Carbon Sources ◽  
Nitrogen Sources ◽  
Biodiesel Production ◽  
Potential Candidate ◽  
Potential Source ◽  
Microalgae Biomass ◽  
Basal Media

<p>Microalgae are considered as one of the potential source of biodiesel for the future. The search to obtain the potential strains from the algal diversity capable of producing oil is critical for sustainable production of biodiesel. In the present study, microalgae biomass with oil/lipid accumulation capability and their morphological features was isolated from Lake Abaya and Chamo. The algal biomass was cultivated <em>in vitro</em> and media optimization for maximum biomass was done using different basal media, BG-11 medium, and Chu -10. In addition the various carbon sources, nitrogen sources, pH and temperature were considered in this study for optimization. Green algae <em>Oedogonium</em>, <em>Chlorella </em>and <em>Cladophora</em> species were observed to be dominant species and the maximum oil per dry algal biomass was found to be from <em>Oedogonium</em> sp. Thus from the present study for the cultivation of the selected algae, BG-11 medium supplemented with tryptone (0.2%) sucrose (2%) and pH- 6 with incubation temperature of 30<sup>0</sup>C was found to be suitable.  These results suggest that <em>Oedogonium</em> sp. has several desirable features that make it a potential candidate for biodiesel production.</p>

scholarly journals Optimisation of culture conditions for gamma-aminobutyric acid production in rice bran extracts

2021 ◽  
Vol 63 (1) ◽  
pp. 42-48
Author(s):  
Dai Hung Ngo ◽  
◽  
Quoc Tuan Tran ◽  
Thi Nhat Hang Nguyen ◽  
Dai Nghiep Ngo ◽  
...  
Keyword(s):  
Rice Bran ◽  
Monosodium Glutamate ◽  
Carbon Sources ◽  
Nitrogen Sources ◽  
Culture Conditions ◽  
High Potential ◽  
Aminobutyric Acid ◽  
Process Conditions ◽  
Gamma Aminobutyric Acid ◽  
Gaba Production

Gamma-aminobutyric acid (GABA) is a potent bioactive component that widely exists in both plants and animals, has numerous health benefits. This study aimed to optimise the fermentation process conditions for the growth of Lactobacillus fermentum from rice bran extracts that have high potential to produce GABA. GABA content was assessed by thin-layer chromatography (TLC) method. In this study, fermenting conditions for medium production of GABA by L. fermentum from rice bran extracts were optimised. L. fermentum showed high potential for GABA-producing ability. Some factors influencing the GABA production such as carbon sources, nitrogen sources, mineral salt sources, substrate concentration of monosodium glutamate (MSG), pH, and the time of fermentation were investigated. When the L. fermentum is cultivated in the rice bran extracts medium supplemented with 1.5% lactose, 2% yeast extract, and 1% MSG with pH 6.0 in 48 h, this strain showed high GABA at a concentration of 736 mg/l.

scholarly journals Optimization of Cellulase Production from Bacteria Isolated from Soil

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Sonia Sethi ◽  
Aparna Datta ◽  
B. Lal Gupta ◽  
Saksham Gupta
Keyword(s):  
Bacillus Subtilis ◽  
Carbon Source ◽  
Pseudomonas Fluorescens ◽  
Carbon Sources ◽  
Nitrogen Sources ◽  
Fermentation Medium ◽  
Cellulase Production ◽  
Culture Conditions ◽  
Optimum Conditions ◽  
E Coli

Cellulase-producing bacteria were isolated from soil and identified as Pseudomonas fluorescens, Bacillus subtilIs, E. coli, and Serratia marcescens. Optimization of the fermentation medium for maximum cellulase production was carried out. The culture conditions like pH, temperature, carbon sources, and nitrogen sources were optimized. The optimum conditions found for cellulase production were 40°C at pH 10 with glucose as carbon source and ammonium sulphate as nitrogen source, and coconut cake stimulates the production of cellulase. Among bacteria, Pseudomonas fluorescens is the best cellulase producer among the four followed by Bacillus subtilis, E. coli, and Serratia marscens.

Effects of culture conditions on yield of Shiga-like toxin-IIv from Escherichia coli

1989 ◽  
Vol 35 (6) ◽  
pp. 623-629 ◽  
Author(s):  
D. L. MacLeod ◽  
C. L. Gyles
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Mitomycin C ◽  
Incubation Temperature ◽  
Culture Media ◽  
Carbon Sources ◽  
Culture Conditions ◽  
Edema Disease ◽  
E Coli ◽  
Aerobic Culture

The effects of selected culture conditions on production of Shiga-like toxin-II variant by an edema disease strain of Escherichia coli (412) and E. coli TB1 (pCG6) containing the cloned genes for Shiga-like toxin-II variant were examined. Incubation time, culture media, incubation temperature, starting pH of the culture medium, aeration, static culture, anaerobiosis, carbon sources, amino acids, antibiotics, and mitomycin C were investigated. The study showed that Shiga-like toxin-II variant was primarily cell associated and that strain TB1 (pCG6) produced as much as 100 times more toxin than did strain 412. Culture conditions that resulted in the greatest yield of Shiga-like toxin-II variant were incubation at 37 °C for 24 h with shaking in syncase broth initially adjusted to pH 8.5. Aerobic culture with shaking resulted in higher yields of Shiga-like toxin-II variant than did static aerobic or anaerobic culture. Addition of various carbon sources or amino acids, or tetracycline, lincomycin, or trimethoprim: sulfadoxine did not increase yields of toxin. The amount of Shiga-like toxin-II variant in supernatant preparations from strain TB1 (pCG6) was significantly increased by addition of mitomycin C to the culture medium.Key words: Shiga-like toxin-II variant, verotoxin, Escherichia coli, edema disease, culture conditions.

scholarly journals Optimization of Agrase Production by Alkaline Pseudomonas aeruginosa ZSL-2 Using Taguchi Experimental Design

2014 ◽  
Vol 17 ◽  
pp. 180-193 ◽  
Author(s):  
M. Ziayoddin ◽  
Junna Lalitha ◽  
Manohar Shinde
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Orthogonal Array ◽  
Carbon Sources ◽  
Nitrogen Sources ◽  
Culture Conditions ◽  
Media Culture ◽  
Orthogonal Array Design ◽  
Array Design ◽  
Factors Affecting ◽  
Fermentation Parameters

The culture conditions for the production of extracellular agarase by Pseudomonas aeruginosa ZSL-2 were optimized using One-Factor-At-A-Time combined with orthogonal array design. One-Factor-At-A-Time method investigates the effect of time, temperature, NaCl, carbon sources, nitrogen sources and pH on agarase production. The optimized culture conditions obtained from the statistical analysis were temperature of 30 °C, pH 8.5, NH4NO3 2 g L-1 and agar 3 g L-1. The L9 orthogonal array design was used to select the fermentation parameters influencing the yield of agarase. The order of the factors affecting the fermentation process was found to be NH4NO3 > pH > agar > temperature, with temperature playing a significant role on the agarase production (p < 0.10). The higher yields than those in basal media culture were obtained in the final optimized medium with activity of 0.439 ± 0.013 U ml-1. Extracellular agarase hydrolysed agar into a range of oligosaccharides which were analysed by LC-ESI-MS spectrometry as anhydrogalactose, galactose, agarobiose, agarotetrose and agarohexaose.

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