Production of an antifungal antibiotic by Streptomyces aburaviensis 1DA-28

A broad-spectrum antifungal Streptomyces isolate, 1DA-28, from Indian soil has been characterized and identified as Streptomyces aburaviensis var. ablastmyceticus (MTCC 2469). Nutritional and cultural conditions for the production of antibiotic by this organism under shake-flask conditions have been determined. Antibiotic production in synthetic medium reached the maximum on the 5th day of incubation at 30 degreesC. Glucose and starch were found to be the best carbon sources while NH4NO3 was preferred as nitrogen source. Optimum temperature and pH for antibiotic production were 32 degreesC and 7.4, respectively. Phosphate at a concentration sub-optimal for growth enhanced antibiotic production. Supplementation of medium with casein hydrolysate improved both growth and antibiotic titre but yeast extract exhibited marked inhibition.     

Oxidative destruction of the heptaene antibiotic levorin

Levorin destruction in oxygen, argon or air at various temperature levels was studied. It was found that destruction of the antibiotic molecule was mainly due to its interaction with oxygen. As a result the heptaenic chromophore was oxidized and triene and tetraene formed. Oxidation of levorin was accompanied by splitting out of paraaminoacetophenone. Destruction of levorin in the absence of oxygen was retarded.     

Effect of liquid culture requirements on antifungal antibiotic production by Streptomyces rimosus MY02

Streptomyces rimosus MY02 was isolated from a soil sample which was collected from the northeast of China. The effect of medium components (i.e. carbon and nitrogen sources) and other culture requirements (i.e. initial pH and temperature) on production of antifungal antibiotics by S. rimosus MY02 was investigated in our work. The best conditions for the strain MY02 in 250-ml Erlenmeyer flask, for example, initial pH, temperature, medium capacity, agitation rate, seed age, inoculum size and growth period, were 6.0, 28 degrees C, 50 ml, 180 rpm, 4 days, 10% (v/v) and 120 h, respectively. Components and dosage of the medium, which effect antibiotic production, were determined by uniform design combined with regression analysis; meanwhile, a regression model was established. The components and dosage of the best medium were starch, 53.313 g; defatted peanut powder, 9.376 g; (NH(4))(2)SO(4), 6.244 g; and NaCl, 5.836 g; in 1l of distilled water. Residual values obtained between the observed values by experiments and predicted values by the model are very low, and this result showed that the experimental results were well in consistence with the calculation results via the model. The antifungal antibiotic production by S. rimosus MY02 was improved by optimization of the components and culture requirements. The diameter of inhibition zone of the culture supernatant from S. rimosus MY02 against Fusarium oxysporium f sp. cucumarinum was 33.19 mm.     

A study of antifungal antibiotic production by Streptomyces chattanoogensis MTCC 3423 using full factorial design

AIMS: The understanding of the dynamics of surface microbial colonization with concomitant monitoring of biofilm formation requires the development of biofilm reactors that enable direct and real-time evaluation under different hydrodynamic conditions. METHODS AND RESULTS: This work proposes and discusses a simple flow cell reactor that provides a means to monitoring biofilm growth by periodical removing biofilm-attached slides for off-line, both non-destructive and destructive biofilm analyses. This is managed without the stoppage of the flow, thus reducing the contamination and the disturbance of the biofilm development. With this flow cell, biofilm growth and respiratory activity can be easily followed, either in well-defined laboratory conditions or in an industrial environment. CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY: The reproducible and typical biofilm development curves obtained, validated this flow cell and confirmed its potential for different biofilm-related studies, which can include biocidal treatment.     

Streptoverticillium griseoviridum n. sp., a producer of the candidin-amphotericin B group, antifungal heptaene nonaromatic antibiotic 0185]

An actinomyceteous strain LIA-0185 producing a heptaenic non-aromatic antibiotic of the candidin type was isolated from a soil sample taken in the Georgian SSR under the programme of screening antifungal antibiotics. The taxonomic study of the strain showed that it belonged to the series of viridoflavum and had the following main taxonomic features: the sporophores in the whorls, straight, remote: the aerial mycelium from yellow to dark-olive-grey; the substrate mycelium olive; the soluble pigment absent; the melanine pigment was produced on the peptone medium; the culture formed H2S; assimilated glucose, mannose, inozide and to a lesser extent fructose; did not assimilate arabinose, xylose, sucrose, lactose, ramnose and raffinose. The strain inhibited the growth of yeast and fungi, grampositive bacteria and actinomycetes and produced a complex of non-aromatic heptaenic antibiotics. The actinomycete differed from the other whorl cultures. It was classified as a new species Sv. griseoviridum sp. nov. The antibiotic complex was a mixture of 2 components, i. e. I and II present approximately in equal amounts. Component II was analogous to candidin. Component I was a new original substance.     

Isolation and structure elucidation of a new antifungal and antibacterial antibiotic produced by Streptomyces sp. 201

An antibacterial and antifungal antibiotic was isolated from the culture filtrate of Streptomyces sp. 201, and its structure was determined as 2-methyl-heptyl isonicotinate by extensive use of NMR spectroscopy. The compound exhibited marked antimicrobial activity against Bacillus subtilis, Shigella sp., Klebsiella sp., E. coli, Proteus mirabilis, and the pathogenic fungi, Fusarium moniliforme, F. semitectum, F. oxysporum, F. solani and Rhizoctonia solani.     

JU-2, a novel phosphorous-containing antifungal antibiotic from Streptomyces kanamyceticus M8

A novel phosphorous-containing antifungal antibiotic JU-2 was isolated from Streptomyces kanamyceticus M8. Quantitative chemical analysis shows the presence of two phenylalanines, two glucose, one linoleic acid, one crucic acid and one phosphonamide moiety per molcule of the antibiotic. JU-2 shows strong inhibitory activity against various pathogenic and non-pathogenic fungi but no activity against bacteria and yeast.     

Ester antibiotic accumulation by Streptomyces hygroscopicus

In an attempt to maximize the ester antibiotic production by Streptomyces hygroscopicus D1.5, its efficacy was found to be enhanced by manipulation of the nutrient and physical environment. The two stage fermentation using seed inoculum (10% v/v) resulted in better production while fermentation continued for 5 days in pH 7.0 at 30 degrees C. Enhanced yield was also observed in whole cell immobilization. Under entrapment, maximum yield was achieved at 7th and 9th day of fermentation for mycelia and spore. In addition, the beads could be reused up to the 3rd cycle.     

Streptomyces coerulatus, a producer of the nonaromatic heptaene, LIA-0735

An actinomycete designated as Streptomyces coerulatus LIA-0735 was isolated from a soil sample collected in the Alma-Ata region. The strain produces a nonaromatic heptaenic antibiotic with a very low inhibitory effect on the growth of gram positive bacteria, yeasts and actinomycetes. By a number of features antibiotic LIA-0735 differs from the known heptaens of the nonaromatic group.     

Synthesis, absolute stereochemistry and molecular design of the new antifungal and antibacterial antibiotic produced by Streptomyces sp.201

The absolute stereochemistry of the new antifungal and antibacterial antibiotic produced by Streptomyces sp.201 has been established by achieving the total synthesis of the product. A series of analogues have also been synthesized by changing the side chain and their bioactivity assessed against different microbial strains. Among them, 1e (R = C8H17) was found to be the most potent with MIC of 8 microg/mL against Mycobacterium tuberculosis, 12 microg/mL against Escherichia coli and 16 microg/mL against Bacillus subtilis 6 microg/mL against Proteus vulgaris. This was followed by 1b (R = C5H11) with MIC of 10-20 microg/mL range and 1d (R = C7H15) with MIC of 14-24 g/mL, whereas 1a (R = C4H9) and 1f (R = C18H35) were found to be completely inactive. Besides, 1c (R = C6H13) showed certain extent of antibacterial activity in the range of 24-50 microg/mL. Mycobacterium tuberculosis was very sensitive to 1e (R = C8H17) with MIC of 8 microg/mL. Antifungal activity of analogues 1d (R = C7H15) and 1e, (R = C8H17) against Fusarium oxysporum and Rhizoctonia solani were found promising with MFCs in the 15-18 microg/mL range.     

Pactamycin Production by Streptomyces pactum

The optimal fermentation conditions for the production of pactamycin, a new antitumor antibiotic, by Streptomyces pactum var. pactum were investigated. The optimal pH range for growth was 6.5 to 7.0. The optimal temperature for the growth of the culture and the production of the antibiotic was investigated in a medium containing Cerelose, blackstrap molasses, Pabst yeast, Kay Soy, CaCO₃, and KCl. Since maximal growth and maximal production efficiency was obtained at 32 C, all subsequent fermentations were conducted at this temperature. Pactamycin was bound to the mycelium in different amounts, depending on the fermentation conditions, and could be extracted with acetone. Good yields (216 μg/ml) of pactamycin could be obtained in a medium containing Cerelose, soy-peptone, calcium carbonate, and potassium chloride. Analysis of the biochemical changes during fermentation indicated that pactamycin was produced during the later autolytic phase.     

L-Asparaginase Production by Streptomyces griseus

Streptomyces griseus ATCC 10137 synthesizes about 1 IU of L-asparaginase/100 ml of a 4% peptone medium. The enzyme has a pH optimum of 8.5 which is comparable to that of the L-asparaginase derived from Escherichia coli which has antitumor properties.     

Production of Anticapsin by Streptomyces griseoplanus

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Production of Anticapsin by Streptomyces griseoplanus

Anticapsin is a new fermentation product which inhibits formation of the hyaluronic acid capsule of Streptococcus pyogenes. Production of this metabolite in a complex medium by S. griseoplanus is enhanced by high levels of carbohydrate. A number of carbon sources support biosynthesis but sucrose is most effective, the optimum level being 150 g/liter. Neither glucose nor fructose, alone or in combination, serves as an equivalent substitute for sucrose. The addition of dibasic potassium phosphate to the medium further increases anticapsin production. Dissolved oxygen levels are important for synthesis and stability of the metabolite. Anticapsular activity diminishes rapidly in previously aerated broths which are held under static conditions. This decrease does not occur in pasteurized broths or unpasteurized filtrates.     

Production of the antifungal peptide antibiotic,iturin by Bacillus subtilis NB22 in solid state fermentation

Production of iturin, an antifungal peptide effective at suppressing phytopathogens, by Bacillus subtilis NB22 was investigated in solid state fermentation (SSF) using soy bean curd residue (okara). In scale-up from 15 g to 3 kg, aeration, temperature, and moisture content were controlling factors for the efficient production of iturin. It was found that solid state fermentation was 6–8 times more efficient with respect to iturin productivity than submerged fermentation on the basis of unit wet weight. Higher productivity in selective production of specific components of iturin which are stronger inhibitors of plant pathogens was also confirmed in SSF.