Bioconversion of 9-monoacetyl-josamycin to josamycin by Streptomyces olivochromogenes

Some species of Streptomyces including S. olivochromogenes var. abashirensis were found to liberate 9-acetyl groups of artificial josamycin derivatives, such as 9-monoacetyl-josamycin and 9,2′-diacetyl-josamycin, but not to liberate 3-acetyl and 4″-isovaleryl groups of josamycin or its derivatives. 3-Deacetyl-josamycin which is a by-product in the josamycin fermentation is chemically converted to 9-monoacetyl-josamycin as well as josamycin. Therefore, this bioconversion of 9-monoacetyl-josamycin to josamycin as described here may enable 3-deacetyl-josamycin to be used as a useful resource for the manufacture of josamycin.     

Scopafungin, a Crystalline Antibiotic Produced by Streptomyces hygroscopicus var. enhygrus var. nova

Scopafungin (U-29,479) is a crystalline, nonpolyenic antimicrobial agent obtained from the culture broth of Streptomyces hygroscopicus var. enhygrus var. nova UC-2397. Scopafungin inhibits, in vitro, a variety of pathogenic fungi, yeasts, and gram-positive bacteria.     

Cell wall composition of Streptomyces roseoflavus var. roseofungini and its Nocardia-like variant

The composition of cell walls was comparatively studied in Streptomyces roseoflavus var. roseofungini 1128 and in its variant 1-68. In the logarithmic phase of growth, the content of teichoic acid in the cell wall of the parent culture was four times as high as in the cell wall of the variant. The cell walls of the parent culture contained 5 to 7 times more O-lysyl residues not only due to a higher content of teichoic acid in the walls but also owing to a lower content of lysyl groups in the teichoic acid of the variant. An additional polysaccharide comprising galactose and glucosamine was found in the cell wall of the variant but not in the parent strain. The peptidoglycan of the both cultures had a structure typical of Streptomyces spp.; its content in the cell walls of the two cultures was identical (ca. 50% of the dry cell wall biomass weight). The results are discussed in connection with the peculiarities of the variant hyphal septation.     

Thaimycins,new anthelmintic and antiprotozoal antibiotics produced by Streptomyces michiganensis var. amylolyticus var. nova

Summary A new microorganism, isolated in our laboratories and identified as Streptomyces michiganensis var. amylolyticus var. nova is described.Thaimycins can be obtained by submerged fermentation of this microorganism on a suitable culture medium.Three new related compounds, thaimycins A, B and C have been obtained and characterized by their physical and chemical properties.Data on the antiprotozoal and anthelmintic activities in vitro as well as in vivo are reported.     

Morphological quantification of pellets in Streptomyces hygroscopicus var. geldanus fermentation broths using a flatbed scanner

An image analysis technique has been developed to allow high throughput morphological characterisation of microbial fermentation broths containing spherical pellets greater than 100 m in diameter. Images of stained Streptomyces hygroscopicus var. geldanus culture samples at three different inoculum levels were captured using a flatbed scanner, at a resolution of 21 m per pixel (1200 dots per inch) and subsequently analysed leading to the generation of a morphological profile of each sample. The time taken for image capture and analysis of a prepared sample, containing approx. 2000 particles, was 3 min 6 s.     

Glucose kinases from Streptomyces peucetius var. caesius

Glucose kinases (Glks) are enzymes of the glycolytic pathway involved in glucose phosphorylation. These enzymes can use various phosphoryl donors such as ATP, ADP, and polyphosphate. In several streptomycetes, ATP-glucose kinase (ATP-Glk) has been widely studied and regarded as the main glucose phosphorylating enzyme and is likely a regulatory protein in carbon catabolite repression. In cell extracts from the doxorubicin overproducing strain Streptomyces peucetius var. caesius, grown in glucose, a polyphosphate-dependent Glk (Pp-Glk) was detected by zymogram. Maximum activity was observed during the stationary growth phase (48 h) of cells grown in 100 mM glucose. No activity was detected when 20 mM glutamate was used as the only carbon source, supporting a role for glucose in inducing this enzyme. Contrary to wild-type strains of Streptomyces coelicolor, Streptomyces lividans, and Streptomyces thermocarboxydus K-155, S. peucetius var. caesius produced 1.8 times more Pp-Glk than ATP-Glk. In addition, this microorganism produced five and four times more Pp-Glk and anthracyclines, respectively, than its wild-type S. peucetius parent strain, supporting a role for this enzyme in antibiotic production in the overproducer strain. A cloned 726-bp DNA fragment from S. peucetius var. caesius encoded a putative Pp-Glk, with amino acid identities between 83 and 87 % to orthologous sequences from the above-cited streptomycetes. The cloned fragment showed the polyphosphate-binding sequences GXDIGGXXIK, TXGTGIGSA, and KEX₍₄₎SWXXWA. Sequences for the Zn-binding motif were not detected in this fragment, suggesting that Pp-Glk is not related to the Glk ROK family of proteins.     

Genetic Recombination in Streptomyces bikiniensis var. zorbonensis

A genetic recombination system in Streptomyces bikiniensis var. zorbonensis is described. This strain produces a mixture of antibiotics including zorbamycin and zorbonomycin B and C. A genetic map has been constructed from data obtained from an analysis of haploid recombinants which shows linkage relationships of 17 marker loci. Determination of map location has been made for three different loci affecting antibiotic biosynthesis in this strain.     

Product inhibition in simultaneous saccharification and fermentation of cellulose into lactic acid

The product, lactic acid, strongly inhibited microbial activity in lactic acid fermentation. The volumetric productivity declined from 1.19 g/l.h with zero lactic acid (control) to only 0.18 g/l.h when lactic acid reached 65 g/l. Lactic acid also inhibited cellulase activity but less severely than the inhibition on microbial activity as lactic acid above 90 g/l was needed for 50% inhibition. A gradual deterioration of the Simultaneous Saccharification and Fermentation (SSF) process occurred with the build-up of lactic acid and the rate-controlling step in SSF shifted from hydrolysis to fermentation as the bioprocess proceeded.     

Rapid ethanol fermentation of cellulose hydrolysate. II. Product and substrate inhibition and optimization of fermentor design

High concentrations of both ethanol and sugar in the fermentation broth inhibit the growth of yeast cells and the rate of product formation. Inhibitory effects of ethanol on the yeast strain Saccharomyces cerevisiae NRRL-Y-132 were studied in batch and continuous chemostat cultures. Growth was limited by either glucose or ethanol. Feed medium was supplemented with different ethanol concentrations. Ethanol was found to inhibit growth and the activity of yeast to produce ethanol in a noncompetitive manner. A linear kinetic pattern for growth and product formation was observed according to μ = μ_m (1 – P/P_m) and v = v_m (1 – P/P_m′), where μ_m is the maximum specific growth rate at P = 0 (hr^?1); P_m is the maximum specific product formation rate at P = 0 (hr^?1); P_m is the maximum ethanol concentration above which cells do not grow (g/liter); P_m′ is the maximum ethanol concentration above which cells do not produce ethanol (g/liter). Substrate inhibition studies were carried out using short-time experimental techniques under aerobic and anaerobic condition. The degree of substrate inhibition was found to be higher than that has been reported for ethanol fermentation of pure sugar. The kinetic relationships thus obtained were used to compute growth, substrate utilization, and alcohol production patterns and have been discussed with reference to batch and continuous fermentation of enzymatically produced bagasse hydrolysate.     

Antibiotic production by Streptomyces aureofaciens using self-cycling fermentation

The self-cycling frementation (;rSCF) technique was applied to culture of Streptomyces aureofaciens. SCF is a method of continuous fermentation in which the metabolism of a microorganism is monitored by a measurement such as dissolved oxygen. These data are sent to a computer to allow it to control the system. Tetracycline production was observed only at exceedingly low iron concentrations in the growth medium. Repeatability of cycles was found to be dependent upon the presence of tetracycline in the fermentation broth as well as the strain of microorganism grown in the fermentor. Tetracycline was produced by an improved specific rate when compared to results in the literature for this organism grown using the batch method. (c) 1994 John Wiley & Sons, Inc.     

Phosphate inhibition of secondary metabolism in Streptomyces hygroscopicus and its reversal by cyclic AMP

Inorganic phosphate inhibited the biosynthesis of the macrolide antibiotic turimycin in different strains of Streptomyces hygroscopicus. In the wild type strain a depression was observed with increasing phosphate concentrations. A total inhibition was found at 0.1 M phosphate. In a high producing mutant a minimum of turimycin production occured when the phosphate concentration was between 5 mM and 10 mM. Above this concentration the antibiotic synthesis increased again but the production period shifted to a later period of cultivation. Addition of inorganic phosphate resulted in an initial increase of intracellular cyclic AMP content. But a second elevation characterizing the normal level of cyclic AMP throughout the growth phase was prevented by phosphate. Exogenous cyclic AMP as well as positive effectors of the adenylyl cyclase system were able to overcome the phosphate suppression. Cyclic AMP abolished the reduction of protein synthesis following phosphate addition and caused the reappearance of a protein band which may be responsible for the turimycin biosynthesis.     

Isolation,taxonomic and fermentation studies on a new strain of Streptomyces arenae var ukrainiana producing a tetraene antibiotic

A Streptomyces strain UK10 was isolated from Ukrainian soil and identified by taxonomical studies as Streptomyces arenae var ukrainiana. HA-2-91 was isolated from the biomass of S. arenae var ukrainiana and is supposedly a polyene macrolide antibiotic belonging to the tetraene group. HA-2-91 showed promising antifungal activity (in vitro) against yeasts and filamentous fungi, including plant pathogens and dermatophytes and was found to be less toxic in mice than nystatin and rimocidin.     

Acyl-CoA pool and acyl-CoA thioesterase in Streptomyces noursei var. polifungini.

The size of acyl-CoA pool in S. noursei var. polifungini was found to be associated with the antibiotic-synthesizing ability, and was negatively correlated with both the thio-esterase activity (acetyl-CoA hydrolase, EC 3.1.2.1) and its affinity towards acetyl-CoA and propionyl-CoA. The apparent Michaelis constants with acetyl-CoA and propionyl-CoA were 33 times 10(-5) and 6.6 times 10(-5) M in the low producing strain, and 8.5 times 10(-4) and 1.2 times 10(-4) M in the high producing strain, respectively.     

Photosynthesis-dependent removal of 2,4-dichlorophenol by Chlorella fusca var. vacuolata

Of 7 green algae, Chlorella fusca var. vacuolata removed about 23% of 2,4-dichlorophenol (DCP) at 10–80 M after 4 d when grown photoautotrophically. Removal of DCP was growth-dependent and was suppressed dose-dependently by the photosynthesis inhibitor, 3-(3,4-dichlorophenyl)-1,1-dimethyl urea.     

Intraspecific hybridization and its bearing on chromosome evolution inVicia narbonensis (Fabaceae)

Nine accessions ofVicia narbonensis, considered to be the wild progenitor of faba bean (Vicia faba), were investigated to ascertain the nature and extent of intraspecific karyotypic polymorphism. The chromosome complements resolved into four distinct types (A, B, C, D), and the meiotic data of F₁ hybrids (A × B, B × C, A × C) revealed that alteration in chromosome morphology is the result of segmental interchanges. The interchange complexes indicate that the parents differ from each other by 1 to 2 interchanges. It is also evident that karyotype B, and not A as previously reported, is the normal karyotype of the species, and A and C are single homozygotes for unequal interchange. The comparative karyomorphology of the parents and the hybrids, and of two interchange heterozygotes of four chromosomes each in F₁ hybrids of A × C shows that the chromosomes involved in the single interchange homozygotes (A, C) are not common and the breaks in both interchanges occurred in short and long arms of the involved chromosomes. Identification of the interchanged chromosomes in the complements and the frequency of ring and chain quadrivalents in the heterozygotes enabled location of the breakpoints. The present results provide probably the first example indicating that interchange homozygosity (A) is not only firmly established but also has enabled the species to spread further by adapting to a wide range of habitats. — The genetic relationships between A and D are very different. All seven chromosome pairs in D could be distinguished from A, and for that matter, B and C as well. From the meiotic pairing properties it is also amply clear that genome D is well differentiated from A and possibly B, and C, and deserves special status.     

Production of transglutaminase by Streptomyces isolates in solid-state fermentation

Aims:  To screen Streptomyces isolates for transglutaminase (TGase) production in solid-state fermentation (SSF) on various substrates.
Methods and Results:  Streptomyces mobaraensis NRRL B-3729, Streptomyces paucisporogenes ATCC 12596 and Streptomyces platensis NRRL 2364 strains were screened for extracellular TGase production in SSF on different substrates. High-protein-content beans, peas and lentils proved to be the best substrates. Good TGase production was obtained on liver kidney beans and green mung beans in a 4- to 6-day SSF. Temperature optima of the enzymes varied between 45 to 50°C. Molecular weight determined by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS PAGE) indicated similar size (∼37 kDa) for all three enzymes. TGase was the dominating protein band on SDS PAGE for two Streptomyces strains in SSF extracts. Other enzymes were present in smaller quantities.
Conclusions:  Streptomyces mobaraensis NRRL B-3729, S. paucisporogenes ATCC 12596 and S. platensis NRRL 2364 strains were successfully propagated under SSF conditions on crushed/milled liver kidney bean and green mung bean to obtain good level of TGase.
Significance and Impact of the Study:  Owing to much reduced production cost and direct applicability, SSF TGase without downstream processing (cheap in situ enzyme, crude enzyme) may be an excellent candidate for some nonfood applications.     

Carbon dioxide fixation by the mycelium of the actinomycete Streptomyces chrysomallus var. macrotetrolidi

The mycelium of Streptomyces chryzomallus var. macrotetrolidi producing the macrotetrolide antibiotic nonactin was shown to be capable of carbon dioxide fixation. Carbon was found to be incorporated into nonactin and macromolecular compounds in the biomass. Carbon was incorporated within 20 to 40 min of the mycelium incubation with NaH14CO3. Pyruvic and propionic acids stimulated carbon incorporation.