Bioutilization of Chicken Feather Waste by Newly Isolated Keratinolytic Bacteria and Conversion into Protein Hydrolysates with Improved Functionalities.

Chicken feathers are major poultry waste that is difficult to process in its native form due to highly resistant keratin protein in large amounts. In this study, a novel feather-degrading bacterium, Bacillus amyloliquefaciens KB1, was screened from a chicken farm bed (CFB) using morphological and biochemical tests followed by 16s rDNA analysis. Among observed isolates, bacterial isolate (KB1) showed the highest degree of feather degradation (74.78 ± 2.94%) and total soluble protein (205 ± 0.03 mg/g). The optimum fermentation conditions obtained were at 40 °C (temperature), pH 9, and 1% (w/v) feather concentration using response surface methodology in a Box-Behnken design. It produced 260 mg/g of soluble protein and bioactive peptides with 86.16% feather degradation. The amino acid profile showed an increase in the concentration of essential amino acids compared with the feather meal broth. The selection of a safe screening source for this new bacterium in CFB produced hydrolysates with enhanced bioactivity applicable for feed, and cosmetic applications, along with environmental bioremediation.

Optimal Production of Protein Hydrolysates from Monkfish By-Products: Chemical Features and Associated Biological Activities.

The aim of this work was the recovery of protein substrates from monkfish waste (heads and viscera) generated in the on-board processing of this species. Initially, the effect of pH, temperature, and protease concentration was studied on mixtures of a 1:1 ratio (w/v) of monkfish heads/water. The optimal conditions of proteolytic digestion were established at 57.4 °C, pH 8.31, [Alcalase] = 0.05% (v/w) for 3 h of hydrolysis. Later on, a set of hydrolysis at 5L-pH-stat reactor were run under the aforementioned conditions, confirming the validity of the optimization studies for the head and viscera of monkfish. Regarding the chemical properties of the fish protein hydrolysates (FPH), the yield of digestion was higher than 90% in both cases and the degrees of hydrolysis and the soluble protein content were not especially large (<20% and <45 g/L, respectively). In vitro digestibility was higher than 90% and the percentage of essential amino acids ranged from 40 to 42%. Antioxidant activities were higher in viscera FPH, and antihypertensive ability was superior in head FPH. The values of number average molecular weights (Mn) of monkfish hydrolysates were 600 Da in the viscera and 947 Da in the head. The peptide size distribution, obtained by size-exclusion chromatography, indicated that the largest presence of peptides below 1000 Da and 200 Da was observed in the viscera FPH.

Production and Characterization of Antioxidative Hydrolysates and Peptides from Corn Gluten Meal Using Papain, Ficin, and Bromelain.

There has been a growing interest in developing natural antioxidants with high efficiency and low cost. Bioactive protein hydrolysates could be a potential source of natural and safer antioxidants. The objectives of this study were to hydrolyze corn gluten meal using three plant-derived proteases, namely papain, ficin, and bromelain, to produce antioxidative hydrolysates and peptides and to characterize the antioxidant performances using both chemical assays and a ground meat model. The optimum hydrolysis time for papain was 3 h, and for ficin and bromelain was 4 h. The hydrolysates were further separated by sequential ultrafiltration to 5 hydrolysate fractions named F1 to F5 from low molecular weight (MW) (<1 kDa) to high MW range (>10 kDa), which were further characterized for TPC, free radical scavenging capacity against DPPH and ABTS, and metal chelating activity. The fraction F4 produced by papain (CH-P4), F1 produced by ficin (CH-F1), and F3 produced by bromelain (CH-B3) showed the strongest antioxidant activity and yield, respectively. These three fractions were incorporated into ground pork to determine their inhibition effects on lipid oxidation during a 16-day storage period. The inhibition effect was enhanced with the addition of higher amount of hydrolysate (e.g., 1000 vs. 500 mg/kg). The CH-P4 reduced lipid oxidation in ground meat by as much as 30.45%, and CH-B3 reduced oxidation by 27.2% at the same level, but the inhibition was only 13.83% with 1000 mg/kg of CH-F1. The study demonstrated that CGM protein hydrolysates and peptides could be used as naturally derived antioxidant in retarding lipid oxidation and improving product storage stability.

Selective biodegradation of recalcitrant black chicken feathers by a newly isolated thermotolerant bacterium Pseudochrobactrum sp. IY-BUK1 for enhanced production of keratinase and protein-rich hydrolysates.

Black chicken feathers generated in large amount from poultry and slaughter houses are highly recalcitrant to microbial degradation due to their tough structural nature. A novel keratinolytic bacterium that possessed high affinity for black feather was isolated from chicken manure and identified as Pseudochrobactrum sp. IY-BUK1. Keratinase and feather soluble protein were effectively produced by the free living cells of the bacterium in media containing only black feathers and a mixture of equal amount of black-, brown- and white-coloured feathers. Complete degradation of 5 g/L of black feathers was completed in 3 days following optimisation of physico-chemical conditions. However, the bacterium selectively completed the degradation of black feather in a medium containing mixture of feathers in 144 h leaving behind approximately 33% and 45% of brown and white feathers in the medium respectively. Gellan gum-immobilised cells of strain IY-BUK1 enhanced the keratinase production by about 150% and were used repeatedly for ten cycles to degrade 5 g/L of black feather in a semi continuous fermentation of 18 h per cycle with enhanced and stable production of soluble protein. The study demonstrated the potential use of Pseudochrobactrum sp. IY-BUK1 not only in biodegradation of highly recalcitrant black feathers, but also in producing keratinase enzymes and valuable soluble proteins for possible industrial usage.

Preparation of kenaf stem hemicellulosic hydrolysate and its fermentability in microbial production of xylitol by Escherichia coli BL21.

Kenaf (Hibiscus cannabinus L.), a potential fibre crop with a desirably high growth rate, could serve as a sustainable feedstock in the production of xylitol. In this work, the extraction of soluble products of kenaf through dilute nitric-acid hydrolysis was elucidated with respect to three parameters, namely temperature, residence time, and acid concentration. The study will assist in evaluating the performance in terms of xylose recovery. The result point out that the maximum xylose yield of 30.7 g per 100 g of dry kenaf was attained from 2% (v/v) HNO3 at 130 °C for 60 min. The detoxified hydrolysate was incorporated as the primary carbon source for subsequent fermentation by recombinant Escherichia coli and the performance of strain on five different semi-synthetic media on xylitol production were evaluated herein. Among these media, batch cultivation in a basal salt medium (BSM) afforded the highest xylitol yield of 0.35 g/g based on xylose consumption, which corresponded to 92.8% substrate utilization after 38 h. Subsequently, fermentation by E. coli in the xylose-based kenaf hydrolysate supplemented with BSM resulting in 6.8 g/L xylitol which corresponding to xylitol yield of 0.38 g/g. These findings suggested that the use of kenaf as the fermentation feedstock could be advantageous for the development of sustainable xylitol production.

Fish viscera protein hydrolysates: Production, potential applications and functional and bioactive properties.

The aquaculture and fishery chain is an important part of the economy of many countries around the world; in recent years it has experienced significant growth that generates more and more quantities of waste, which are mostly discarded, impacting the environment, despite having a useful chemical composition in various industrial sectors. This article presents a review of the agroindustrial potential of fish wastes, especially viscera, as a source for obtaining native protein and hydrolysates, explaining their production process, chemical composition and functional and bioactive properties that are important to the agricultural, cosmetic, pharmaceutical, food and nutraceutical industry.

Response surface methodology applied to the generation of casein hydrolysates with antioxidant and dipeptidyl peptidase IV inhibitory properties.

BACKGROUND: Hydrolysis parameters affecting the release of dipeptidyl peptidase IV (DPP-IV) inhibitory and antioxidant peptides from milk proteins have not been extensively studied. Therefore, a multifactorial (i.e. pH, temperature and hydrolysis time) composite design was used to optimise the release of bioactive peptides (BAPs) with DPP-IV inhibitory and antioxidant [oxygen radical absorbance capacity (ORAC)] properties from sodium caseinate. RESULTS: Fifteen sodium caseinate hydrolysates (H1-H15) were generated with ProtamexTM , a bacillus proteinase activity. Hydrolysis time (1 to 5 h) had the highest influence on both DPP-IV inhibitory properties and ORAC activity (P < 0.05). Alteration of incubation temperature (40 to 60 °C) and pH (6.5 to 8.0) had an effect on the DPP-IV inhibitory properties but not the ORAC activity of the Protamex sodium caseinate hydrolysates. A multi-functional hydrolysate, H12, was identified having DPP-IV inhibitory (actual: 0.82 ± 0.24 vs. predicted optimum: 0.68 mg mL-1 ) and ORAC (actual: 639 ± 66 vs. predicted optimum: 639 µmol TE g-1 ) activity of the same order (P > 0.05) as the response surface methodology (RSM) predicted optimum bioactivities. CONCLUSION: Generation of milk protein hydrolysates through multifactorial design approaches may aid in the optimal enzymatic release of BAPs with serum glucose lowering and antioxidant properties. © 2016 Society of Chemical Industry.

Production of bioactive protein hydrolysate using the yeasts isolated from soft chhurpi.

The aim of this work was to study the production of bioactive protein hydrolysates using yeasts isolated from chhurpi. For this, a total of 125 proteolytic yeasts were isolated and molecular identification was carried out by analysis of the restriction digestion pattern generated by digesting the PCR amplified internal transcribed spacer region and 5.8S rRNA gene (ITS1-5.8S-ITS2) using three endonucleases (HaeIII, CfoI and HinfI). The results obtained showed that different proteolytic yeasts were dominant in marketed products (Kluyveromyces marxianus and Issatchenkia orientalis) and samples from production centers (Trichosporon asahii, Saccharomyces cerevisiae and Exophiala dermatitidis). Proteolytic strains in individual groups showed their ability to hydrolyze milk protein and enhance antioxidant property. Among the isolates, fermentation using K. marxianus YMP45 and S. cerevisiae YAM14 resulted in higher antioxidant activity. This is the first report on application of yeast isolated from fermented food of North-East India for the production of bioactive protein hydrolysate.

Production of bioactive peptide hydrolysates from deer, sheep, pig and cattle red blood cell fractions using plant and fungal protease preparations.

Protease preparations from plant (papain and bromelain) and fungal (FP400 and FPII) sources were used to hydrolyze the red blood cell fractions (RBCFs) separated from deer, sheep, pig, and cattle abattoir-sourced blood. After 1, 2, 4 and 24h of hydrolysis, the antioxidant and antibacterial activities of the peptide hydrolysates obtained were investigated. The increase in trichloroacetic acid-soluble peptides over the hydrolysis period was examined using the o-phthaldialdehyde (OPA) assay and the hydrolysis profiles were illustrated using SDS-PAGE. Papain generated RBCF hydrolysates exhibited higher ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) compared to those generated with bromelain, FP400 and FPII. At certain concentrations, 24h hydrolysates of RBCF using FP400 and FPII were able to inhibit the growth of Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. The results indicated that the use of proteases from plant or fungal sources can produce animal blood hydrolysates with antioxidant and antimicrobial activities.

Artificial neural networks to model the production of blood protein hydrolysates for plant fertilisation.

BACKGROUND: Amino acid-based fertilisers increase the bioavailability of nitrogen in plants and help withstand stress conditions. Additionally, porcine blood protein hydrolysates are able to supply iron, which is involved in chlorophyll synthesis and improves the availability of nutrients in soil. A high degree of hydrolysis is desirable when producing a protein hydrolysate intended for fertilisation, since it assures a high supply of free amino acids. Given the complexity of enzyme reactions, empirical approaches such as artificial neural networks (ANNs) are preferred for modelisation. RESULTS: Porcine blood meal was hydrolysed for 3 h with subtilisin. The time evolution of the degree of hydrolysis was successfully modelled by means of a feedforward ANN comprising 10 neurons in the hidden layer and trained by the Levenberg-Marquardt algorithm. The ANN model described adequately the influence of pH, temperature, enzyme concentration and reaction time upon the degree of hydrolysis, and was used to estimate the optimal operation conditions (pH 6.67, 56.9 °C, enzyme to substrate ratio of 10 g kg(-1) and 3 h of reaction) leading to the maximum degree of hydrolysis (35.12%). CONCLUSIONS: ANN modelling was a useful tool to model enzymatic reactions and was successfully employed to optimise the degree of hydrolysis.

Genetic and biochemical evidence that recombinant Enterococcus spp. strains expressing gelatinase (GelE) produce bovine milk-derived hydrolysates with high angiotensin converting enzyme-inhibitory activity (ACE-IA).

In this work, genes encoding gelatinase (gelE) and serine proteinase (sprE), two extracellular proteases produced by Enterococcus faecalis DBH18, were cloned in the protein expression vector pMG36c, containing the constitutive P32 promoter, generating the recombinant plasmids pCG, pCSP, and pCGSP encoding gelE, sprE, and gelE-sprE, respectively. Transformation of noncaseinolytic E. faecalis P36, E. faecalis JH2-2, E. faecium AR24, and E. hirae AR14 strains with these plasmids permitted detection of caseinolytic activity only in the strains transformed with pCG or pCGSP. Complementation of a deletion (knockout) mutant of E. faecalis V583 for production of gelatinase (GelE) with pCG unequivocally supported that gelE is responsible for the caseinolytic activity of the transformed strain grown in bovine skim milk (BSM). RP-HPLC-MS/MS analysis of hydrolysates of transformed Enterococcus spp. strains grown in BSM permitted the identification of 38 major peptide fragments including peptides with previously reported angiotensin converting enzyme-inhibitory activity (ACE-IA), antihypertensive activity, and antioxidant activity.

Aminopeptidase from Streptomyces gedanensis as a useful tool for protein hydrolysate preparations with improved functional properties.

UNLABELLED: The aim of the present study was to evaluate the efficiency of amino peptidase (AP) from Streptomyces gedanensis to produce protein hydrolysates (PHs) with better antioxidant, nutritional, and functional properties and to compare it with the PHs produced by commercial protease. Three proteins, soy, casein, and wheat protein were employed to produce their hydrolysates by applying 2% (w/w) AP at optimal conditions of pH 8.5 and temperature 55 °C. The results disclosed that the degree of hydrolysis ranges from 15.93 to 20.68% after 6 h showed better antioxidant activity and functional properties such as solubility, foaming properties, and water holding capacity than the commercial protease treated hydrolysates. AP treated PHs were enriched in Glu followed by Leu, Tyr, Lys, Phe, Asp, Met, His, Ile, Ala, and Val. Therefore, S. gedanensis AP would be an attractive microbial AP with high potential for the preparation of PHs which could offer industrial applications especially in the realm of producing food formulations as food additives in medicine and sport. PRACTICAL APPLICATION: AP from S. gedanensis was found to be the most effective enzyme to produce PHs with good antioxidant, nutritional, and functional properties. The antioxidant and essential amino acids of AP treated PHs unveiled that this amino peptidase could give credence to eliminate the bitter taste by hydrolysis of peptides and could offer interesting possibilities for industrial applications, including debittering of protein hydrolysates. The findings could be useful in the food industry especially in the realm of producing food formulations requiring high protein supplements.

Preparation of antioxidant peptide from egg white protein and improvement of its activities assisted by high-intensity pulsed electric field.

BACKGROUND: Egg white protein powder was hydrolyzed by three proteases-alcalase, trypsin, and pepsin-to produce antioxidant peptides. Three kinds of hydrolysates were prepared under optimal enzymatic parameters that were obtained from the preliminary one-factor-at-a-time test and response surface methodology. Thereafter, three enzymatic hydrolysates were sequentially fractionated by ultrafiltration membranes in cut-off MW of 30, 10, and 1 kDa, and tested in terms of their reducing power (RP). Effects of high-intensity pulsed electric field (PEF) were further investigated on the antioxidant peptides to improve their activities. RESULTS: Alcalase hydrolysates possessed stronger RP ability than the other two hydrolysates, particularly for the fraction within < 1 kDa. After PEF treatment, this fraction showed an improvement of RP ability within 4 h; however, the effects were reversible. High-performance liquid chromatographic analysis showed some MW changes of PEF-treated sample compared with control. CONCLUSIONS: Among the three kinds of proteases, alcalase could be regarded as the most appropriate enzyme for preparation of bioactive peptide from egg white protein, with the best antioxidant activity. Also, PEF showed some effects on the peptide and could be further applied to improve its antioxidant activity.

Biochemical properties and potential applications of recombinant leucine aminopeptidase from Bacillus kaustophilus CCRC 11223.

Experiments were carried out to investigate the effects of various factors on the activity and conformation of recombinant leucine aminopeptidase of Bacillus kaustophilus CCRC 11223 (BkLAP) and potential utilization of BkLAP in the hydrolysis of anchovy protein. Optimal temperature and pH of BkLAP were 70 °C and 8.0 in potassium-phosphate buffer, respectively, and the activity was strongly stimulated by Ni(2+), followed by Mn(2+) and Co(2+). Conformational studies via circular dichroism spectroscopy indicated that various factors could influence the secondary structure of BkLAP to different extents and further induce the changes in enzymatic activity. The secondary structure of BkLAP was slightly modified by Ni(2+) at the concentration of 1×10(-4) M, however, significant changes on the secondary structures of the enzyme were observed when Hg(2+) was added to the concentration of 1×10(-4) M. The potential application of BkLAP was evaluated through combination with the commercial or endogenous enzyme to hydrolysis the anchovy protein. Results showed that combining the BkLAP with other enzymes could significantly increase the degree of hydrolysis and amino acid component of hydrolysate. In this regard, BkLAP is a potential enzyme that can be used in the protein hydrolysate industry.

In situ immobilization of acid protease on mesoporous activated carbon packed column for the production of protein hydrolysates.

The mesoporous activated carbon (MAC) was used as a support material for in situ immobilization of acid protease (AP). The optimum temperature for the activities of both free and immobilized AP was found to be 50 degrees C. The catalytic efficiency of AP-MAC system has significantly been maintained for more than ten consecutive reaction cycles. The functional groups and surface morphology of the AP, MAC and AP-MAC were observed by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The production of protein hydrolysates was carried out from bovine serum albumin (BSA) using AP-MAC packed column and its properties were studied.

Influencia de los parámetros de secado sobre los indicadores fisico-químicos y biológicos de un hidrolizado de proteínas / Influence of the drying parameters on the physicochemical and biological indicators of a protein hydrolisate

Se estudiaron las condiciones de la deshidratación por aspersión de un hidrolizado papaínico proveniente del músculo animal, y se demostró que el parámetro de mayor influencia directa sobre la densidad aparente del polvo resultó la concentración de sólidos totales (43 por ciento), seguidamente de la temperatura en la entrada de la cámara (140 °C) y velocidad del atomizador (21 500 rev/min), ambos de forma inversa. La densidad aparente alcanzó aproximadamente 400 kg m-3 en comparación con la obtenida antes del estudio de 50 kg m-3. Se comprobó que mejores resultados, en cuanto a la densidad aparente, se obtuvieron al deshidratar el hidrolizado a 122 °C en la entrada de la máquina y 90 °C en la salida en comparación con 140 °C en la entrada del equipo. Se demostró que el producto obtenido posee características físico-químicas y bioquímicas favorecedoras del crecimiento de diferentes especies microbianas de colección(AU)

The spraying dehydration conditions of a Papaic hydrolisate from an animal muscle were studied, and it was proved that the parameter with the highest direct influence on the apparent density of the powder was the concentration of total solids (43 percent), followed by the temperature at the inlet of the chamber (140 °C) and the speed of the atomizer (21 500 rev/min), both in an inverse form. The apparent density reached approximately 400 kg m-3 compared with the obtained before the study of 50 kg m-3. As to the apparent density, better results were obtained on dehydrating the hidrolisate at 122 °C in the inlet of the machine and at 90 °C in the outlet, in comparison with 140 °C in the inlet of the equipment. It was proved that the product obtained had physical, chemical and biochemical characteristics that favored the growth of different microbial species of collection(AU)

Influencia de los parámetros de secado sobre los indicadores fisico-químicos y biológicos de un hidrolizado de proteínas / Influence of the drying parameters on the physicochemical and biological indicators of a protein hydrolisate

Se estudiaron las condiciones de la deshidratación por aspersión de un hidrolizado papaínico proveniente del músculo animal, y se demostró que el parámetro de mayor influencia directa sobre la densidad aparente del polvo resultó la concentración de sólidos totales (43 por ciento), seguidamente de la temperatura en la entrada de la cámara (140 °C) y velocidad del atomizador (21 500 rev/min), ambos de forma inversa. La densidad aparente alcanzó aproximadamente 400 kg m-3 en comparación con la obtenida antes del estudio de 50 kg m-3. Se comprobó que mejores resultados, en cuanto a la densidad aparente, se obtuvieron al deshidratar el hidrolizado a 122 °C en la entrada de la máquina y 90 °C en la salida en comparación con 140 °C en la entrada del equipo. Se demostró que el producto obtenido posee características físico-químicas y bioquímicas favorecedoras del crecimiento de diferentes especies microbianas de colección.

The spraying dehydration conditions of a Papaic hydrolisate from an animal muscle were studied, and it was proved that the parameter with the highest direct influence on the apparent density of the powder was the concentration of total solids (43 percent), followed by the temperature at the inlet of the chamber (140 °C) and the speed of the atomizer (21 500 rev/min), both in an inverse form. The apparent density reached approximately 400 kg m-3 compared with the obtained before the study of 50 kg m-3. As to the apparent density, better results were obtained on dehydrating the hidrolisate at 122 °C in the inlet of the machine and at 90 °C in the outlet, in comparison with 140 °C in the inlet of the equipment. It was proved that the product obtained had physical, chemical and biochemical characteristics that favored the growth of different microbial species of collection.

Utilisation of Chlorella vulgaris cell biomass for the production of enzymatic protein hydrolysates.

Studies on enzymatic hydrolysis of cell proteins in green microalgae Chlorella vulgaris 87/1 are described. Different proteases can be used for production of hydrolysates from ethanol extracted algae. The influence of reaction parameters on hydrolysis of extracted biomass with pancreatin was considered, and the composition of hydrolysates (Cv-PH) was investigated in relation to the starting materials. Significant changes in the degree of hydrolysis were observed only during the first 2h and it remained constant throughout the process. An enzyme-substrate ratio of 30-45 units/g algae, an algae concentration of 10-15% and pH values of 7.5-8.0 could be recommended. Differences in the chromatographic patterns of Cv-PH and a hot-extract from Chlorella biomass were observed. Adequate amounts of essential amino acids (44.7%) in relation to the reference pattern of FAO for human nutrition were found, except for sulfur amino acids. Cv-PH could be considered as a potential ingredient in the food industry.

Production of feather protein hydrolysate by keratinolytic bacterium Vibrio sp. kr2.

A feather protein hydrolysate was produced using the keratinolytic bacterium Vibrio sp. strain kr2. Complete feather degradation was observed in medium containing up to 60 g L(-1) raw feathers. Cultivation on 40, 60 or 80 g L(-1) feathers for five days resulted in similar amounts of soluble protein, reaching maximum values around 2.5 g L(-1). Maximum yields of soluble protein were achieved at 30 degrees C and initial pH ranging from 6.0 to 8.0. Strain kr2 was effective in producing keratin hydrolysate from chicken feathers. Bacterial feather hydrolysate has the potential for utilization as an ingredient in animal feed or as organic fertilizer, thereby reducing the environmental impact of feather waste from the poultry industry.

[Hydrolytic and haemolytic activity of Klebsiella pneumoniae and Klebsiella oxytoca]. / Hydrolityczna i hemolitycznaaktywnosc paleczek Klebsiella pneumoniae i Klebsiella oxytoca.

Hydrolytic enzymes and haemolysins are important extracellular substances produced by many bacteria. We investigated 57 K. pneumoniae strains and 40 K. oxytoca strains isolated from clinical materials. We estimated the ability to produce: proteases hydrolyzing milk powder, caseinase, gelatinase, elastase, lecithinase, lipases, DNase and haemolysins on human, sheep and horse erythrocytes on TSA medium with or without 5% Egg Yolk. We detected that K. oxytoca strains produced proteases hydrolyzing milk powder (37.5%), caseinase (15.0%) and gelatinase (17.5%) more frequently than K. pneumoniae strains (respectively 21.0%, 5.3%, 8.9%). None of the analysed Klebsiella spp. strains produced elastase. Only K. pneumoniae strains produced lecithinase (5.3%). Lipases hydrolyzing Tween were produced from 3.5% (for Tween 60 and 80) to 7.0% (for Tween 20). Among K. oxytoca strains only one (2.5%) hydrolyzing Tween 20. DNase was produced by 38.6% of K. pneumoniae strains and by 27.5% K. oxytoca strains. Haemolytic properties on human erythrocytes were detected in 5.3% K. pneumoniae strains on TSA medium and 29,8% on medium with Egg Yolk. In K. oxytoca strains haemolytic properties on human erythrocytes were detected only on medium with Egg Yolk (12.5%). Haemolytic properties on sheep erythrocytes were detected respectively in 21.0% and 22.8% K. pneumoniae strains and in 7.5% K. oxytoca strains on each medium. Haemolytic properties on horse erythrocytes were detected respectively in 33.4% and 52.6% K. pneumoniae strains and in 15.0% and 20.0% K. oxytoca strains.