Folia Microbiologica

Banerjee, U. C.; Vohra, R. M.

doi: 10.1007/bf02814506pmid: 1822835

ACurvularia sp. isolated from soil was found to contain laccase activity toward guaiacol as substrate. The organism produced an extracellular laccase in a medium containing yeast extract, peptone and dextrose. Initial medium pH 4.0 and cultivation temperature 30°C were found to be most suitable for maximum enzyme production. The optimum pH and temperature for laccase activity were found to be 5.2 and 50°C, respectively. Under optimum conditions, the enzyme had aKm (guaiacol) of 0.75 mmol/L and aV of 1.50 CU min−1 ml−1. Some divalent metal ions inhibited laccase activity at very low concentrations.

Famurewa, O.; Olutiola, P. O.

doi: 10.1007/bf02814507pmid: 1822836

Aspergillus chevalieri andPenicillium steckii grew best at 30°C and at pH of 6.5–7.5. Among the carbon sources employed, sucrose supported maximum growth ofA. chevalieri while glucose was best forP. steckii. Growth of both organisms was optimal on ammonium tartrate as the sole source of nitrogen.A. chevalieri andP. steckii grew in synthetic media containing, respectively, soluble or insoluble cellulose as the sole carbon source, releasing a cellulolytic enzyme into the medium. The enzymes from each organism were separated and partially purified by molecular exclusion and ion-exchange chromatography into two components. There was synergism between the components of enzymes from each organism in that they together released more glucose units from insoluble cellulose than could be predicted from their activities alone. The molar mass of the enzymes estimated from the elution volume on Sephadex was approximately 110 kg/mol forA. chevalieri and 94 kg/mol forP. steckii.

Sharma, N.; Bhalla, T. C.; Bhatt, A. K.

doi: 10.1007/bf02814508pmid: N/A

Partial purification of extracellular cellulase ofTrichoderma viride isolated from forest soil was done by ammonium sulfate precipitation of culture supernatant, centrifugation at higher speed, solubilization of protein in sodium acetate buffer and dialysis. The specific activity of cellulase in the culture supernatant, was 136 nkat/mg which was increased by 172% after the completion of final step (234 nkat/mg). The recovery of enzyme was 70%. The enzyme was characterized by demonstration of optimum activity at 55°C and pH 5.0 with 1% carboxymethyl cellulose as substrate.

Nitharwal, P. D.; Gour, H. N.; Agarwal, S.

doi: 10.1007/bf02814509pmid: N/A

A purified culture of the fungal pathogenCurvularia lunata causing leaf blight of pearl millet was used for studies on the production of cell-wall-degrading enzymes. Czapek-Dox medium was found to be the best medium of the five different nutrient media used for the production of cellulase and growth of the fungus. Pectolytic enzymes could not be detected under different cultural conditions. Two-week incubation period, pH 6.0 and temperature 25°C were found to be the most favorable conditions for good growth and maximum production of cellulase by the fungus in present studies. The results are presented and discussed in the light of the earlier findings onC. lunata.

Leuchtenberger, A.; Mayer, G.

doi: 10.1007/bf02814510pmid: 1822837

Mutants ofA. niger K 69/26, prepared by multistep mutagenesis (UV, MNNG, heating) have been screened for pectinase activities. Mutants with altered levels of certain pectinases, such as endo- and exopolygalacturonase (PG vis, red), pectinesterase (PE) and pectinlyase (PL), were isolated. The enzyme activities of the best mutants M 1348/126 were increased 2–3-fold compared to the parent strain after a 6-d cultivation of filamentous mycelium on a shaker. Further mutagenesis of mutants with decreased pectinase activities (e.g. Se3) produced revertants. PG (vis) synthesis of revertant Se5 was increased 1.7 times compared to the control strain K 69/26. Independent of these increased rates, the general level of pectinase activities synthesized by the filamentous mycelium ofA. niger mutants amounts to about 10–20% compared with those produced by aggregated mycelium. It appears that the enzyme synthesis related to mycelium structure is independent of the mechanism which regulates the level of pectinase synthesis within a specific morphological structure.

Bagy, M. M. K.; El-Sharouny, H. M. M.; El-Shanawany, A. A.

doi: 10.1007/bf02814511pmid: 1822838

Increasing the pH from 5 to 9 decreased the toxicity of mercuric chloride, zinc sulfate, lead nitrate, copper sulfate and nickel chloride toward the growth ofAspergillus flavus, Penicillium chrysogenum, Cunninghamella echinulata, Myrothecium verrucaria andPhoma humicola. On the other hand, the toxicity of cadmium chloride was increased by the increasing pH. Also increasing the concentration of organic matter (peptone and yeast extract) from 0.5 to 1.5% induced a significant reduction in the toxicity of all heavy metals toward the growth of all test fungi.

Zeman, R.; Vojtíšek, V.

doi: 10.1007/bf02814512pmid: 1822839

Intact cellsEscherichia coli CCM 2843, exhibiting substantial benzylpenicillin amidase activity, were bound mutually with supporting waste microbial cells, native or treated, to obtain an inexpensive biocatalyst for the production of 6-aminopenicillanic acid (6-APA). The bond was effected by glutaraldehyde (GA) and Sedipur CL-930 (PEI), without any carrier. The optimal concentration of GA was 2%, that of PEI 1%. The optimal biocatalyst was obtained by immobilization of productive cells with their fragments at a mass ratio of 4∶1. The cell aggregates were used for hydrolysis of potassium benzyl-penicillin at a concentration of 5 % to 6-APA. After 25 repeated batch conversions the degree of conversion did not decrease; its average value was 96.4%.

Dixit, A. K.; Kushwaha, R. K. S.

doi: 10.1007/bf02814513pmid: 1726608

Keratinophilic fungi were isolated from feathers of most common Indian birds,viz. domestic chicken (Gallus domesticus), domestic pigeon (Columba livia), house sparrow (Passer domesticus), house crow (Corvus splendens), duck (Anas sp.), rose-ringed parakeet (Psittacula krameri). Out of 87 birds, 58 yielded 4 keratinophilic fungal genera representing 13 fungal species and one sterile mycelium. The isolated fungi were cultured on Sabouraud's dextrose agar at 28±2°C.Chrysosporium species were isolated on most of the birds.Chrysosporium lucknowense andChrysosporium tropicum were the most common fungal species associated with these Indian birds. Maximum occurrence of fungi (47%) was recorded on domestic chickens and the least number of keratinophilic fungi was isolated from the domestic pigeon and duck. The average number of fungi per bird was found to be the 0.44.

Alam, A.

doi: 10.1007/bf02814514pmid: 1822840

A method is presented for the successful decontamination of sparingly soluble pteridine derivatives by microwave irradiation. The method is nondestructive, rapid and effective in eliminating contamination.

Mittal, R.; Sharma, S.

doi: 10.1007/bf02814515pmid: 1822841

Fifteen uroisolates ofE. coli were studies for both cell-free and cell-bound hemolysin production. Estimations were done inTrypticase soy broth (TSB, providing iron-replete medium) TSB +2,2′-bipyridine (providing experimentally created iron-depleted conditions) and pooled normal human urine (providing natural iron-depleted growth medium). In TSB 40% of strains showed no detectable cell-free hemolysin, they were able to produce it in the presence of 2,2′-bipyridine and more so when grown in urine. The cell-bound hemolysin was produced by all the strains in TSB, but in the presence of 2,2′-bipyridine and urine an insignificant increase was observed. All the strains when given 2nd and 3rd passage in urine, were found to elaborate significantly more cell-free as well as cell-bound hemolysin.