A simple and low-cost procedure was developed for the effective processing of native calf skin and blood wastes to produce protein hydrolysates. The method includes extraction of high-molecular-weight protein from the raw material, followed by enzymatic hydrolysis of the extracted residue. The enzymatic hydrolysis was performed by inexpensive commercial subtilisin DY, produced by Bacillus subtilis strain DY possessing high specific activity. The contents of protein, nitrogen, ash, and amino acids of the obtained hydrolysates were determined and compared with those of the commonly used commercial casein hydrolysate (Fluka Biochemica, Switzerland). The newly obtained calf skin hydrolysate, called Eladin, was found to be suitable as a low-cost alternative peptone in growth media of different microorganisms, such as Escherichia coli, Pseudomonas aeruginosa, Salmonella dublin, and Staphylococcus aureus. The method allows utilization of waste materials by converting them into valuable protein products that could find widespread application in microbiologic practice.

The ability of actinomycete strains newly isolated from Antarctic soils to produce keratinolytic enzymes during growth on sheep wool waste was investigated. The strains which displayed highest keratinase activity and identified as Streptomyces flavis 2BG (mesophilic) and Microbispora aerata IMBAS-11A (thermophilic) were selected for a more detailed analysis. The addition of starch to the growth medium affected keratinase secretion by both strains. After 5 days of cultivation, a 6-fold increase in keratinase activity of strain 11A was observed in the presence of 11 g starch/l and a 9-fold increase in keratinase activity of the strain 2BG in the presence of 5 g starch/l. The results obtained showed that both newly isolated strains are very promising for effective processing of native keratinous wastes. To our knowledge, this is the first report of Antarctic actinomycete strains that were able to grow on keratin-containing wastes by producing keratinolytic enzymes.

The bacterium Streptomyces albus has so far never been investigated for tyrosinase activity. The studies presented in this communication show that this bacterium may be a future source for larger production of tyrosinase. The enzyme was purified starting with 5,600 ml of culture filtrate. The crude enzyme was first purified by centrifugation, followed by ammonium sulfate precipitation and ultrafiltration. Then, melanin was removed applying a Servacell DEAE 52 resin, using the batch technique. Thereafter, the crude enzyme was loaded on a SEC Sephacryl S-100 column and, after ultrafiltration, 1.17 mg of purified tyrosinase were obtained. The molecular mass of the purified enzyme was determined by MALDI mass spectrometry to be 30,096 Da which corresponds to the obtained results from SDS-PAGE. Using the diphenol L-DOPA and the monophenol L-tyrosine as substrates, the kinetic parameters for both substrates, Km = 7.8 mM and 0.5 mM and kcat/Km = 157 mM-1 s-1 and 23 mM-1 s-1, respectively, were determined. Maximal activities of the purified enzyme were recorded at pH 7.0. Long-term experiments with Streptomyces albus tyrosinase revealed that storage of the lyophilized enzyme sample at temperatures below zero turned out to be the best. For tyrosinase in buffer containing 20% glycerol, no loss of activity was observed at 4°C and - 60°C

In the course of our screening program for active substances of microbial origin, an antifungal antibiotic complex was isolated from the culture broth of a strain of Streptomyces hygroscopicus B-7 and designated AK-B7. It is a complex ofnon-polyenic antifungal antibiotics, such as scopafungin1}, niphimycin2~4), copiamycin5), neocopiamycin6), guanidylfungins A and B7), azalo