Zone Of Hydrolysis Research Articles

The growth of Thermomyces lanuginosus (TSIKL.) isolates from garden composts and coffee beans on cellulose substrates and xylan at various water activity

Abstract The study was to determine the effect of water activity (0.850; 0.900; 0.950; 0.995; and 0.999 aw) on the growth of T. lanuginosus on solid media containing different cellulose substrates (crystalline cellulose, carboxymethyl cellulose - CMC, fi lter paper, and sawdust) and xylan. The growth of isolates from coffee beans and garden composts were compared. All isolates did not grow on media with aw < 0.950. On media with aw > 0.950, the hydrolysis zones were only observed on xylan and CMC. The highest daily growth and hydrolysis zone rates were mostly obtained at 0.995 aw and the lowest values were observed at 0.950 aw. The coffee beans isolates at 0.950 aw had the CMC hydrolysis coeffi cient 1.7-times higher than that for xylan. The fungal growth (FG) coeffi cient data indicate that the coffee beans isolates were able to utilize CMC and crystalline cellulose for growth and the highest growth rate was obtained at 0.999 aw. Subsequently, the compost isolates were able to grow on all substrates but the highest growth rate was obtained on CMC at 0.950 and 0.999 aw. Thus, coffee beans and composts provide T. lanuginosus isolates with various growth and hydrolytic zone rates in the range of 0.950−0.999 aw.

Kinetics of improved 1,4-alpha-D-glucan glucohydrolase biosynthesis from a newly isolated Aspergillus oryzae IIB-6 and parameter significance analysis by 2-factorial design

Sixteen different mould cultures viz. Aspergillus, Alternaria, Arthroderma, Trichoderma, Fusarium, Penicillium, Rhizopus and Chochliobolus were isolated from the soil samples of Qatar by serial dilution method. The preliminary screening of isolates was done by selecting initial colonies showing relatively bigger zones of starch hydrolysis on nutrient agar plates. The isolates were then subjected to secondary screening by submerged fermentation (SmF). The 1,4-α-D-glucan glucohydrolase (GGH) activity ranged from 1.906-12.675 U/ml/min. The product yield was analysed in dependence of mycelial morphology, biomass level and protein content. The isolate Aspergillus oryzae llB-6 which gave maximum enzyme production was incubated in M3 medium containing 20 g/l starch, 10 g/l lactose, 8.5 g/l yeast extract, 6 g/l corn steep liquor (CSL), 1.2 g/l MgSO4.7H2O, 1.3 g/l NH4Cl, 0.6 g/l CaCl2.2H2O, pH 5 at 30±2°C and 200 rpm. On the basis of kinetic variables, notably Qp (0.058±0.01a U/g/h), Yp/s (0.308±0.03ab U/g) and qp (0.210±0.032abc U/g fungal biomass/h), A. oryzae IIB-6 was found to be a hyper producer of GGH (LSD 0.0345) compared to A. kawachii IIB-2. A noticeable enhancement in enzyme activity of over 30% was observed (13.917±1.01 U/ml/min) when the process parameters viz. cultural conditions (pH 5, incubation period 72 h) and nutritional requirements (6 g/l CSL, 9.5 g/l yeast extract, 10 g/l starch, 20 g/l lactose) were further optimized using a 2-factorial Plackett-Burman design. The model terms were found to be highly significant (HS, p≤0.05), indicating the potential utility of the culture (dof~3).

Organic Anion–Driven Solubilization of Precipitated and Sorbed Phytate Improves Hydrolysis by Phytases and Bioavailability to Nicotiana tabacum

Improved plant access to native soil phosphorus (P) species such as phytate (metal ion derivatives of myo-inositol hexakisphosphate (IHP)) could minimize agricultural dependence on nonrenewable mineral phosphates and reduce surface water pollution. Nicotiana tabacum plant lines with unique organic anion (OA) and phytase production patterns were used to investigate the effect of OA-driven solubilization on the bioavailability of precipitated and sorbed IHP. Organic anions released IHP sorbed to goethite (Gt) by chelation or reductive dissolution mechanisms in the order: ascorbate > citrate > oxalate > pyruvate > acetate. Transgenic tobacco overexpressing Peniophora lycii phytase (PHY) and a MATE-type citrate transporter (CIT) exuded 2.2- to 2.6-fold higher OA compared with that of wild-type plants. The PHY plants had 33-fold higher exudate phytase activity (6.0 × 10−2 nkat plant−1 day−1) compared with those of wild-type and CIT plants, produced the largest zone of iron-IHP hydrolysis in agar media, and incorporated the most shoot P (2.3 μg) when grown on Gt-IHP. Plants grown on IHP at 2× Gt saturation (0.26 mmol/L) were 10-fold higher in shoot P compared with the 1× Gt condition (0.13 mmol/L IHP) with PHY plants approaching excess P status (1 % shoot P). The addition of Gt diminished shoot P in plants grown without P (−70 to −80 %) and with phosphate (−50 %) or IHP (−100 %); the exception was the high citrate–exuding plant line (21 nmol citrate plant−1 day−1), for which phosphate uptake was only 20 % reduced. Plant OA production mitigates P inhibition by Gt when weakly sorbing phosphate species are supplied or when high phytase production by plants can maximize the hydrolysis of IHP.

Isolation and screening of thermophilic cellulolytic bacteria from compost piles

Cellulose, a major polysaccharide found in agricultural residues and industrial and municipal wastes. In the present study thermophilic cellulolytic microorganisms were isolated. The isolates were tested for their cellulytic activity. The enzyme production from potent isolates was optimised using cellulose basal broth medium. Activity of partially purified enzyme was determined. The most potent thermophilic cellulolytic isolates were identified as Bacillus subtilis. The crude cellulase enzyme concentrated at 80-85% ammonium sulfate produced highest zone of hydrolysis. The enzymatic degradation of cellulose waste has been suggested as a feasible alternative for the conversion of lignocelluloses substrate into fermentable sugars and application for biofuel production. Scientific World, Vol. 10, No. 10, July 2012 p43-46 DOI: http://dx.doi.org/10.3126/sw.v10i10.6861

Production of cellulases by fungal cultures isolated from forest litter soil

The aims of this study were the isolation and screening of fungal cultures from forest litter soil for cellulases production. In the present study, four fungal cultures were isolated and identified. Among these fungal cultures, three belonged to the genus Aspergillus and one belonged to the genus Pencillium. These fungal cultures were tested to find their ability to produce cellulases, that catalyze the degradation of cellulose, which is a linear polymer made of glucose subunits linked by beta-1, 4 glycosidic bonds. The fungal isolate 3 (Aspergillus sp.) was noticed to show maximum zone of hydrolysis of carboxy-methyl cellulose and produce higher titers of cellulases including exoglucanase, endoglucanase and beta -D-glucosidase. The activities of the cellulases were determined by Filter paper assay (FPA), Carboxy-methly cellulase assay (CMCase) and beta -D-glucosidase assay respectively. The total soluble sugar and extracellular protein contents of the fungal filtrates were also determined.

Detection of Xanthomonas axonopodis pv. Phaseoli and Pseudomonas savastanoi pv. Phaseolicola on bean seed using a Milk-tween medium

Bean production is threaten by phytopathogenic bacteria causing agents of blights, Xanthomonas axonopodis pv. phaseoli (Xap) and Pseudomonas savastanoi pv. phaseolicola (Psp). Since there is no satisfactory chemical control for the disease, the recommended measures are preventive and include use of healthy seed, crop rotation, deep plowing and use of resistant cultivars. In this work we involved a detection method for isolation of Xap and Psp from bean seed to semi-selective medium Milk Agar Tween (MT). On this medium, Xap formed yellow, mucoid and convex colonies with two hydrolysis zones (less milk and more enlightened), and Psp formed whitish-cream, flat and round colonies. The identification of Xap and Psp was confirmed using the ELISA and PCR. Due to its selectivity, easy preparation and possibility of simultaneous detection of bacteria Xap and Psp, MT medium can be recommended for routine test of seed health for local seed or seed from import.

Optimisation of the Chitinase Production by Serratia Marcescens DSM 30121T and Biological Control of Locusts

Serratia marcescens DSM 30121T was tested for their chitinolytic activity on colloidal chitin agar. The production of the chitinase by Serratia marcescens DSM 30121Twas optimized by using of different parameters such as temperature, pH-value, colloidal chitin concentration and incubation time. The obtained results showed that the maximum chitinase production (0.556 U/ml) was observed at the pH-value of 6, at 30°C. Similarly, the recorded maximum chitinase production (0.368 U/ml) was obtained in the presence of 2% of colloidal chitin concentration in the culture medium after 144 h incubation time. Furthermore, Serratia marcescens DSM 30121 T showed clear zones of hydrolysis of colloidal chitin on agar. Therefore, the present study showed that Serratia marcescens DSM 30121 T is good source for chitinase production. Moreover, the strain Serratia marcescens DSM 30121 T can be used for biological control of locusts.

Recovery of Chromium from the Tannery Wastewater by Use of Bacillus Subtilis in Gujranwala, Pakistan

Tanneries discharge wastes without any treatments on the vast areas of vacant land around them. Untreated effluents contain toxic materials like hexavalent chromium and sulphides which accumulate in soils and cause many health hazards. Hexavalent chromium is toxic and carcinogenic and is being extensively used in the tanning industry of Pakistan. The tannery wastewater samples were collected from two tanneries in Gujranwala, Pakistan. Chromium in these samples was determined using fractionation technique, spectrophotometry and MIBK extraction procedure. These samples were analyzed to recover chromium and chrome cake was purified using chemical treatment which can be used in recycling process. Enzyme was used to recover chromium from the samples. Two strains S1 and S2 of the Bacillus subtilis (isolated and identified from soil and tannery wastewater respectively) were used for enzymatic processing. Isolates were screened for extracellular protease activity. The strain S2 of the Bacillus subtilis showed maximum zones of hydrolysis (2.3cm) and proteolytic activity of 107 PU/ml at 65 0 C temperature, 150 rpm agitation speed and7.5 pH on Shake Flask Fermentation. The One-step and the Two-step methods were employed for chromium recovery using the S2 strain of the Bacillus subtilis. From the One-step method 96% chromium was recovered from sample-A and 92% from the sample-B. From the Two-step method of chromium recovery 98% of chromium was recovered from the sample-A and 97% from the sample-B. This paper evaluates the alternative treatment options used to treat, recover or recycle chromium from the waste water in order to minimize the environmental pollution.

Isolation and Characterization of Cellulose-decomposing Bacteria Inhabiting Sawdust and Coffee Residue Composts

Clarifying the identity and enzymatic activities of microorganisms associated with the decomposition of organic materials is expected to contribute to the evaluation and improvement of composting processes. In this study, we examined the cellulolytic and hemicellulolytic abilities of bacteria isolated from sawdust compost (SDC) and coffee residue compost (CRC). Cellulolytic bacteria were isolated using Dubos mineral salt agar containing azurine cross-linked (AZCL) HE-cellulose. Bacterial identification was performed based on the sequence analysis of 16S rRNA genes, and cellulase, xylanase, β-glucanase, mannanase, and protease activities were characterized using insoluble AZCL-linked substrates. Eleven isolates were obtained from SDC and 10 isolates from CRC. DNA analysis indicated that the isolates from SDC and CRC belonged to the genera Streptomyces, Microbispora, and Paenibacillus, and the genera Streptomyces, Microbispora, and Cohnella, respectively. Microbispora was the most dominant genus in both compost types. All isolates, with the exception of two isolates lacking mannanase activity, showed cellulase, xylanase, β-glucanase, and mannanase activities. Based on enzyme activities expressed as the ratio of hydrolysis zone diameter to colony diameter, it was suggested that the species of Microbispora (SDCB8, SDCB9) and Paenibacillus (SDCB10, SDCB11) in SDC and Microbispora (CRCB2, CRCB6) and Cohnella (CRCB9, CRCB10) in CRC contribute to efficient cellulolytic and hemicellulolytic processes during composting.

Screening and identification of polyhydroxyalkanoates producing bacteria and biochemical characterization of their possible application

Polyhydroxyalkanoates (PHAs) accumulating bacteria were isolated under various selective conditions such as pH, salt concentrations and types of heavy metal. Fifty strains of bacterial isolates were found to belong to Bacillus, Proteus, Pseudomonas, Aeromonas, Alcaligenes and Chromobacterium, based on phenotypical features and genotypic investigation. Only twenty five bacterial isolates were selected and observed for the production of PHAs. Interestingly, bacteria belonging to Firmucutes Bacillus sp. produced a high amount of PHAs. The maximum PHAs were accumulated by B. licheniformis PHA 007 at 68.80% of dry cell weight (DCW). Pseudomonas sp., Aeromonas sp., Alcaligenes sp. and Chromobacterium sp. were recorded to produce a moderate amount of PHAs, varying from 10.00-44.32% of DCW. The enzymatic activity was preliminarily analyzed by the ratio of the clear zone diameter to colony diameter. Bacillus gave the highest ratio of hydrolysis zone which corresponds to the highest hydrolytic enzyme activities. Bacillus licheniformis PHA 007 had the highest lipase and protease activity at 2.1 and 5.1, respectively. However, the highest amylase activity was observed in Bacillus sp. PHA 023 at 1.4. Determination of metabolic characteristics was also investigated to check for their ability to consume a wide range of substrates. Bacillus, Aeromonas sp. and Alcaligenes sp. had great ability to utilize a variety of substrates. To decrease high PHA cost, different sources of cheap substrates were tested for the production of PHAs. Bacillus cereus PHA 008 gave the maximal yield of PHA production (64.09% of DCW) when cultivated in anaerobically treated POME. In addition, the accumulation of PHA copolymers such as 3-hydroxyvalerate and 3-hydroxyhexanoate was also observed in Bacillus and Pseudomomas sp. strain 012 and 045, respectively. Eight of the nine isolates accumulated a significant amount of PHAs when inexpensive carbon sources were used as substrates. Here it varied from 1.69% of DCW by B. licheniformis PHA 007 to 64.09% of DCW by B. cereus PHA 008.

Identification of xylanase producing Bacillus licheniformis strain C1 and properties of crude xylanase

In the present investigation xylanase producing bacteria was isolated from compost. A total of 95 xylanolytic bacteria were isolated on oat spelt xylan agar medium and screened by the xylanolysis method. Out of these 95 isolates, only one bacterial isolates, strain C1 was selected for further study on the basis of zone of hydrolysis on xylan-congo red agar plate. This strain was identified by 16S rDNA analysis. The phylogenetic analysis using 16S rDNA sequence data showed that isolate C1 showed highest nucleotide identity of 98% with Bacillus licheniformis strain CICC 10181 (GenBank accession no. GQ375235) and identified as Bacillus licheniformis strain C1. Bacillus licheniformis strain C1 was gram positive and rod shaped. Morphology of Bacillus licheniformis strain C1 showed- smooth texture, medium size, opaque transparency, creamish-white colour and serrated margin. Maximal xylanase production for Bacillus licheniformis strain C1 was achieved at the incubation period of 48 h. Xylanase and cellulase activities were determined as 20.0 U/ml and 1.3 U/ml, respectively. The optimum pH and optimum temperature for xylanase activity was found to be 7.0 and 60°C, respectively. Xylanase was found to be thermostable at 60°C for 1h and retained 90% of its activity upto 6 h at this temperature. Approximately, 74% and 70% of its activity was retained at 70°C and 80°C respectively, after 6 h of incubation. All of these properties of the Bacillus licheniformis strain C1 xylanase make the suitability of this enzyme for its use in feed and baking industry.

Extracellular deoxyribonuclease production by periodontal bacteria

Whilst certain bacteria have long been known to secrete extracellular deoxyribonuclease (DNase), the purpose in microbial physiology was unclear. Recently, however, this enzyme has been demonstrated to confer enhanced virulence, enabling bacteria to evade the host's immune defence of extruded DNA/chromatin filaments, termed neutrophil extracellular traps (NETs). As NETs have recently been identified in infected periodontal tissue, the aim of this study was to screen periodontal bacteria for extracellular DNase activity. To determine whether DNase activity was membrane bound or secreted, 34 periodontal bacteria were cultured in broth and on agar plates. Pelleted bacteria and supernatants from broth cultures were analysed for their ability to degrade DNA, with relative activity levels determined using an agarose gel electrophoresis assay. Following culture on DNA-supplemented agar, expression was determined by the presence of a zone of hydrolysis and DNase activity related to colony size. Twenty-seven bacteria, including red and orange complex members Porphyromonas gingivalis, Tannerella forsythia, Fusobacterium nucleatum, Parvimonas micra, Prevotella intermedia, Streptococcus constellatus, Campylobacter rectus and Prevotella nigrescens, were observed to express extracellular DNase activity. Differences in DNase activity were noted, however, when bacteria were assayed in different culture states. Analysis of the activity of secreted DNase from bacterial broth cultures confirmed their ability to degrade NETs. The present study demonstrates, for the first time, that DNase activity is a relatively common property of bacteria associated with advanced periodontal disease. Further work is required to determine the importance of this bacterial DNase activity in the pathogenesis of periodontitis.

Characterisation of protease activity in extracellular products secreted by Giardia duodenalis trophozoites treated with propolis

Results from our laboratory revealed propolis activity on Giardia trophozoites proliferation. Since therapeutic agents can inhibit the activity of proteases related to relevant biologic and physiologic processes of parasites, this study was undertaken to characterise the proteolytic activity of excretory/secretory products (ESP) of trophozoites treated with propolis. ESP was obtained from culture supernatants of trophozoites exposed to 250 and 500 µg mL−1 of propolis. ESP were tested in sodium dodecyl sulfate-polyacrylamide gel electrophoresis for the protein profiles and the protease activity was assayed in gelatin-containing gels. Synthetic inhibitors were used to characterise the protease classes. Treated and non-treated ESP showed a similar protein and hydrolysis pattern. A simple pattern of protein composed by five evident bands of approximately 167, 132, 79, 61 and 51 kDa was found, and the zymograms comprised hydrolysis zones distributed from >170 to 23 kDa. No inhibition was seen on protease activity of propolis-treated trophozoites, whose hydrolysis pattern was similar to control. One may conclude that both ESP degraded gelatin and the activity was predominantly due to cysteine proteases. Although propolis had no effect on the proteolytic activity, further studies could identify the active constituents responsible for propolis antigiardial activity and their mechanisms of action.

Isolation of the polysaccharidase-producing bacteria from the gut of sea snail, Batillus cornutus

This study was conducted to isolate microorganisms from the gut of the marine turban shell, Batillus cornutus, which inhabits the mainland of South Korea and primarily feeds on brown algae. We were interested in isolating such gut bacteria by considering their potential to produce the polysaccharidases required for digestion of brown seaweeds and isolated three different bacteria from the gut of Batillus cornutus. The isolated bacteria were identified as Bacillus sp. JMP-A, Bacillus sp. JMP-B and Staphylococcus sp. JMP-C. The organisms were evaluated for their ability to produce polysaccharidases such as cellulase, alginate lyase, laminarinase and kelp-lyase. Bacillus sp. JMP-A and Bacillus sp. JMP-B showed a clear zone of CMC hydrolysis with a radius 1.10 (±0.057) and 3.88 cm (±0.088), respectively, whereas Staphylococcus sp. JMP-C showed no zone of CMC hydrolysis. SEM analysis confirmed that the ability of the bacterial isolates to degrade kelp differs and is correlated with kelp-lyase production. The cell free extract of the Bacillus sp. JMP-A isolate showed the highest activities of CM-cellulase, α-cellulase, laminarinase and kelp-lyase, which were 22.76, 27.10, 66.59 and 64.36 U/mg, respectively. Meanwhile, the amount of sugars released was higher during the saccharification of kelp by dialyzed intracellular enzymes of the bacterial isolates than when dialyzed extracellular enzyme was used. Experimental results of dialyzed enzymatic saccharification of the kelp demonstrated that use of partially purified enzymes was effective for glucose production.

Pectinolytic yeast isolates for cold-active polygalacturonase production

Abstract Pectin rich cold stored spoiled fruits, vegetables and cold soils were screened and different pectinolytic isolates were obtained by enrichment culturing and ruthenium red plate assay. Among the primary isolates 10–15% were yeast isolates. Six isolates with higher zones of pectin hydrolysis were selected and tested for polygalacturonase (PGU) production at room temperature (25 °C) and at 5 °C. One isolate identified as Saccharomyces sp. with highest polygalacturonase activity at 5 °C was used for enzyme production using raw fruit pectins as substrates. The isolate was identified by preliminary cultural, morphological and sugar fermentation tests. PGU production was high in raw pectin substrates like orange peel (21 U/ml), apple peel (20 U/ml ), mango peel (19 U/ml), grape must (18 U/ml) and guava peel (15 U/ml). Selected Saccharomyces sp. was found to grow at room temperature and produce good polygalacturonase active at 5 °C. Cold-active PGU could have ample application in fruit juice clarification as these conditions are milder and also prevent spoilage. The present study concentrated on enzyme production using the cheaper raw pectin rich substrates. Industrial relevance The manuscript contains information on the cold active polygalacturonase produced by yeast at room temperature. It has industrial application for fruit juice clarification at cold (mild) conditions as it is a cold active enzyme. Also the enzyme is produced at room temperature by yeast considered as a GRAS organism. Therefore, it is a significant observation by the authors.

Prevalence of Thermoactinomyces thalpophilus and T. sacchari strains with biotechnological potential at hot springs and soils from West Anatolia in Turkey

Hot spring sediment and soil samples from West Anatolia in Turkey were investigated for the occurrence of thermophilic Actinomycetes. Isolation was done using Actinomycetes isolation agar (AIA), starch casein agar and glycerol yeast extract agar at 55 °C. Extracellular protease activity of the isolates were screened by using AIA plus 1% casein according to the hydrolysis zones surrounding the colonies. Antimicrobial activities of the isolates were also screened by using streaked plate method against a panel of test bacteria. Identification of the isolates was made by cultural, physiological characteristics and 16S rDNA sequence similarity. Sixty-seven thermophilic Actinomycetes isolates were classified in Thermoactinomyces thalpophilus and T. sacchari species. Among these, 62 isolates (92.5%) were found to be extracellular protease producers and 38 isolates (56.7%) were found active against methicillin resistant Staphylococcus aureus and Enterococcus faecalis. Based on these results, we suggest that the thermophilic actinomycetes, which are a part of the biodiversity of the hot springs and soils from West Anatolia in Turkey, are promising sources for novel enzymes and antimicrobial compounds.

Partial purification and antifungal profile of chitinase produced by Streptomyces tendae TK-VL_333

Production of chitinase by Streptomyces tendae strain TK-VL_333 isolated from laterite soils of the Guntur region, India, was studied in chitin yeast extract salts (CYS) broth. The effect of cultural and nutritional conditions on chitinase productivity of the strain was recorded. The strain elaborated high yields of chitinase when cultured in 1% w/v chitin-supplemented CYS broth containing 0.5% (w/v) xylose and 0.25% (w/v) yeast extract with an initial pH 7 and incubated at temperature 30°C for 72 h. In addition, this strain could utilize fungal biomass as a chitin supplement for chitinase production. The molecular weight of the enzyme purified by ammonium sulphate precipitation (80%) and Sephadex G-100 gel filtration was determined as 45 kDa by SDS-PAGE analysis. The partially purified enzyme was tested for colloidal chitin hydrolysis as well as antifungal activity. It showed a clear zone of colloidal chitin hydrolysis on chitin agar plates, and antifungal activity against Aspergillus niger and Fusarium oxysporum. This is the first report of the optimization and partial purification of chitinase produced by a terrestrial S. tendae.

Characterization of alkaline thermostable keratinolytic protease from thermoalkalophilic Bacillus halodurans JB 99 exhibiting dehairing activity

A thermostable alkaline protease produced from Bacillus sp. JB 99 exhibited significant keratinolytic and dehairing activity. The enzyme was purified by ammonium sulphate precipitation followed by CM-cellulose and Sephadex G-100 chromatography and resulted in 13.6 fold purification with 23.8% of recovery. The specific activity of purified enzyme was 2989.6Umg−l. Purified protease had a molecular weight of 29kDa and appeared as a single band. Gelatin zymogram analysis also revealed a clear hydrolytic zone, which corresponded to the band obtained with SDS-PAGE. The optimum pH and temperature for the keratinolytic activity was pH 11.0 and 70°C respectively and half life of protease was 70°C for 4h. N-terminal amino acid sequence of purified enzyme exhibited extensive homology with other thermostable alkaline proteases and inhibition by PMSF indicated serine type of protease. The Km and Vmax of protease for keratin substrate were 3.8±0.5mgml−1 and 15.1±1.6μmmin−1mg−1 and casein were 3.3±0.4mgml−l and 15.6±0.9μmmin−1mg−1 respectively. The enzyme efficiently dehaired buffalo and goat hide without damaging the collagen layer, which makes it a potential candidate for application in leather industry to avoid pollution problem associated with the use of chemicals in the industry. The enzyme also degraded chicken feathers in presence of reducing agent which can help poultry industry in management of keratin-rich waste and obtaining value added products.

Detection and identification of Xanthomonas axonopodis pv. phaseoli on bean seed collected in Serbia

Laboratory assays were conducted to detect and identify Xanthomonas axonopodis pv. phaseoli on bean seeds collected from naturally contaminated commercial crops. Semi-selective media, viz. Xanthomonas campestris pv. phaseoli agar and milk tween agar were used to detect the bacterium from whole bean seed extract. Colonies of the bacterium were yellow, mucoid and convex on these media and zones of hydrolysis formed around them. The pathogenicity of the strains was confirmed by stem inoculation of young bean plants. Identification of the strains was proved by using rapid methods (ELISA and PCR). The results showed the presence of seed-borne X. axonopodis pv. phaseoli in 20 out of the 23 assayed bean cultivars that are commercially grown in Serbia. These results indicate that the seed of the bean cultivars grown in our country is highly infected by the bacterium. Key words: Common bacterial blight, detection, identification, seed-borne.

Fungal isolates from natural pectic substrates for polygalacturonase and multienzyme production

Pectin rich wastes and waste dump yard soils were screened and eighty pectinolytic fungal isolates were obtained by enrichment culturing and ruthenium red plate assay. Eight isolates with higher zones of pectin hydrolysis were selected and tested for polygalacturonase production. One isolate identified as Aspergillus awamori MTCC 9166 with highest polygalacturonase activity was tested for utilization of raw pectins for enzyme production. Polygalacturonase production was high in raw pectin sources like Orange peel (16.8 U/ml) Jack fruit rind (38 U/ml) Carrot peel (36U/ml) and Beet root peel (24U/ml). Selected Aspergillus awamori MTCC 9166 was found to be having good polygalacturonase, xylanase, cellulase and weak amylase and protease activities. This isolate with multi-enzyme production could have application for enzymes production and degradation of fruit and vegetable waste in the process of urban waste disposal.