Chrysosporium Keratinophilum Research Articles

A Comparative Study of Caffeine Degradation by Four Different Fungi

ABSTRACT The objective of the present study is to investigate the caffeine-degrading abilities of different fungi and to apply this knowledge to environmental remediation and industrial decaffeination process. Chrysosporium keratinophilum, Gliocladium roseum, Fusarium solani, and Aspergillus restrictus were isolated from the coffee pulp obtained from a coffee estate. Pure cultures of fungi were isolated on standard conventional potato dextrose broth (PDB) medium and authenticated. Pure cultures were subjected to a caffeine tolerance study at different concentrations of caffeine (1–8 g/L) in potato dextrose agar (PDA) and minimal media. On PDA, Fusarium solani could tolerate caffeine concentration up to 8 g/L, whereas Chrysosporium keratinophilum, Gliocladium roseum, and Aspergillus restrictus could tolerate up to 6 g/L. On minimal agar medium containing different concentrations of caffeine (1–8 g/L), Fusarium solani tolerated up to 8 g/L and the other fungi up to 2 g/L. A time-bound caffeine degradation study was undertaken at 1 g/L concentration of caffeine and glucose in nitrogen-containing and nitrogen-free liquid minimal media by subjecting the four fungi to shake flask culture at 120 rpm and 30°C. Degradation of caffeine up to 7 days at 24-h intervals was analyzed by high-performance liquid chromatography (HPLC). Gliocladium roseum followed by Aspergillus restrictus showed maximum degradation of caffeine at 0.47 and 0.3 mg/ml, respectively, by 96 h in nitrogen-containing minimal medium, whereas Fusarium solani showed maximum degradation of caffeine by 48 h (0.35 mg/ml) and Chrysosporium keratinophilum by 72 h (0.29 g/ml). In nitrogen-free minimal medium, Chrysosporium keratinophilum showed maximum degradation of caffeine at 72 h (0.45 mg/ml), followed by Gliocladium roseum, Fusarium solani (0.3 mg/ml), and Aspergillus restrictus (0.25 mg/ml) at 96 h. Overall, Chrysosporium keratinophilum showed a comparatively higher rate of caffeine degradation in minimal medium with or without a nitrogen source as compared with the other three fungi, indicating that nitrogen affects caffeine metabolism.

SOIL MICROMYCETES AND VEGETATION CHANGES ASSOCIATED WITH VEGETATIVE COVER DESTRUCTION ON CHOSEN LOCALITIES OF TATRY MOUNTAINS - FIRST APPROACH

AbstractĎugova O., Barančokova M., Krajči J., Barančok P.: Soil micromycetes and vegetation changes associated with vegetative cover destruction on chosen localities of Tatry Mountains - first approach. Ekologia (Bratislava), Vol. 32, No. 2, p. 158-172, 2013.Species composition of soil micromycetes and vegetation and its changes associated with vegetative cover destruction were observed in four localities of Tatry Mts. Three research plots with different extent of vegetation destruction on each locality were subjectively chosen: control plots with almost no destruction of vegetation and soil cover (C), partially disturbed plots (B) and plots with high level of soil cover destruction where cover of herb layer was less than 20% (A). Plant species composition of control plots was characterised by the highest level of taxonomical diversity, highest cover of herb and moss layer and represented by alpine herb and grass communities on siliceous bedrock (Juncion trifidi alliance) and alpine and subalpine plant communities on calcareous bedrock (Seslerion tatrae alliance). Devastation of soil and vegetation on B and A plots was performed particularly by decreasing of herb layer cover and changes in species composition: species as Vaccinium myrtillus, Vaccinium vitis-idaea and Calluna vulgaris were absent, whereas Poa alpina, Potentilla aurea, Agrostis rupestris or Avenella flexuosa occurred on devastated plots often. From investigated soils 43 species of soil micromycetes were identified. Control plot of each locality was represented by the highest taxonomical diversity of soil micromycetes. The number of species significantly decreased on plots with successive destruction of vegetation cover (B and A). Several species were identified in just one case (Penicillium digitatum (pers.:Fr.) Sacc., Chrysosporium keratinophilum D.Frey ex J.W. Carmich. etc.). The outcomes showed that soil microorganisms as well as vascular plants react on destruction of soil cover very sensitively.

Synthesis of new 3-aryl-4-(3-aryl-4,5-dihydro-1H-pyrazol-5-yl)-1-phenyl-1H-pyrazole derivatives as potential antimicrobial agents

New (E)-1-aryl-3-(3-aryl-1-phenyl-1H-pyrazol-4-yl)prop-2-en-1-ones 6 (pyrazolic chalcones) were synthesized from Claisen–Schmidt reaction of 3-aryl-1-phenylpyrazol-4-carboxaldehydes 4 with several acetophenone derivatives 5. Subsequently, the cyclocondensation reaction of chalcones 6 with phenylhydrazine in acetic acid medium afforded the new 3-aryl-4-(3-aryl-4,5-dihydro-1H-pyrazol-5-yl)-1-phenyl-1H-pyrazoles 7. The synthesized compounds were characterized by spectral studies and evaluated for their in vitro antibacterial activity against three pathogenic bacterial strains, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, and in vitro antifungal activity against three pathogenic fungal strains Aspergillus flavus, Chrysosporium keratinophilum, and Candida albicans.

Fungal-mediated nano silver: an effective adulticide against mosquito

Fungi as such are known to be an effective mosquito control agent. In the present investigation, the effect of silver nanoparticles synthesized with Chrysosporium keratinophilum, Verticillium lecanii, and Fusarium oxysporum f.sp. pisi has been evaluated against the adult mosquito of filariasis vector Culex quinquefasciatus. The silver nanoparticles were characterized by using the UV-Vis spectrophotometer and X-ray diffraction techniques. The micrographs of silver nanoparticles were obtained by transmission electron microscope and scanning electron microscope. Elemental analysis on single particle was carried out by EDX analysis. The characterization study confirmed different shapes and sizes of silver nanoparticles. The efficacy test was performed at five different concentrations for a period of 24 h by the probit analysis. The C. quinquefasciatus has shown higher efficacy against the silver nanoparticles synthesized with C. keratinophilum and V. lecanii (lethal concentration (LC)(50) 0.19 and 0.4 μl/cm(2); LC(90) 2.4 and 3.2 μl/cm(2); and LC(99) 4.0 and 5.6 μl/cm(2)) after 22 h of exposure. While the silver nanoparticles synthesized with F. oxysporum f.sp. pisi were found to be less effective against the C. quinquefasciatus, the silver nanoparticles synthesized by C. keratinophilum and V. lecanii were found to be more effective than those generated with the help of F. oxysporum f.sp. pisi and C. quinquefasciatus. The use of fungus-mediated silver nanoparticles is a rapid, environmentally safer, and greener approach for vector control strategy and is adaptable globally.

Epidemiological investigation of keratinophilic fungi from soils of Djerba (Tunisia)

Epidemiological investigation of keratinophilic fungi in soil has been carried out in different parts of the world. However, our knowledge of the present occurrence and distribution of keratinophilic fungi in Tunisian soils remains unknown. This study was carried out to evaluate the epidemiological characteristics of keratinophilic fungi in the soils collected in Djerba (South of Tunisia). One hundred and forty one soil samples were collected from various sites in Djerba and screened for the presence of keratinophilic fungi and related dermatophytes using hair-baiting technique. Fungi were identified using macro- and micro-morphological features. Among them, 29 (20.6%) soil samples were positive. Seven species were isolated in the following order of dominance: Chrysosporium keratinophilum (48.3%), Microsporum gypseum (41.4%), C. tropicum (10.4%), C. parvum (3.45%), C. anamorph of Anixiopsis stercoraris (3.45%), C. anamorph of Arthroderma cuniculi (3.45%) and Chaetomium sp. (3.45%). The association of M. gypseum and C. keratinophilum was detected in 13.8% of positive soils. Sixty-nine percent of fungi were found in organic matter rich soil. Our results revealed a higher prevalence of keratinophilic fungi in the regions far from the sea (33.3%) than in those near the sea (11.1%) with a statistically significant difference (P=0.001). All keratinophilic fungi were isolated from soils with pH ranging from 6.2 to 7.6. Our study showed that keratinophilic fungi were present in the various soils of Djerba. They may represent a risk to human health.

Species diversity of keratinophilic fungi in various soil types

Abstract Keratinophilic fungi are a highly specialized, keratin-degrading ecological group. They live in natural environments, mostly in the keratinrich remains of dead animal in the soil. We investigated species diversity in four types of soils with different physico-chemical properties. The strain material was identified based on morphological characters. Different representatives of Chrysosporium and geophilic dermatophytes dominated depending on soil pH. Geophilic dermatophytes were represented by one species, Trichophyton ajelloi, and the Chrysosporium group was represented by Chrysosporium keratinophilum. The frequency of Trichophyton ajelloi increased with an increase in pH, and it reached the maximum in strongly acidic soil (podzol), unlike the Chrysosporium group. The frequency of Chrysosporium keratinophilum was positively correlated with the content of humus, nitrogen, CaCO3 and phosphorus in the soils.

Isolation of keratinophilic fungi from soil in Isfahan province, Iran

To evaluate the epidemiology of keratophilic fungi in Isfahan province, Iran. The present research has been conducted on soil samples collected from 16 townships of Isfahan province. For isolate geophilic dermatophytes and keratinophilic fungi, the keratin baiting technique has been applied. Of 800soil samples examined, 588 (73.5%) keratinophilic fungi were isolated. The present studied recognized 727 isolates including 16 species of 11genus, as follows: Chrysosporium keratinophilum (31.4%), C. pannicola (16.9%), C. tropicum (15.4%), Microsporum gypseum (12.4%), Chrysosporium spp. (9.9%), C. indicum (7%), Sepedonium spp. (3.3%), Malbranchia spp. (1%), Trichophyton terrestre (0.8%), T. ajelloi and Paecilomyces lilacinus (0.4%), Engyodontium album and Acremonium spp. (0.3%), Curvularia spp., Fusarium spp. and Ulocladium spp. (0.1%). In this study, E. album was isolated for the first time in this country (Iran). The frequency these keratinophilic fungi are discussed in relation to different agents such as soil pH. This study contributes to the knowledge of keratophilic fungi in Iran.

Prevalence of keratinophilic fungi in soils of St. Kitts and Nevis

Information on the prevalence of keratinophilic fungi in West Indies is scanty. Occurrence of keratinophilic fungi in soils of St. Kitts and Nevis has not been investigated previously. The prevalence of keratinophilic fungi was investigated in 108 samples of soils of varying habitats from St. Kitts and 55 such samples from Nevis by hair-baiting technique. Fungal growths appearing on the hair baits after four to eight weeks of incubation at room temperature were microscopically examined and cultured on mycological media. Cultures were identified on the basis of colonial and microscopic features. Forty-nine (45%) of the samples from St. Kitts and 38 (69%) from Nevis were positive for keratinophilic fungi. Microsporum gypseum complex, a well-known geophilic dermatophyte, was the most frequently recovered species being present in 15.7% of soils of St. Kitts and 40% of soils of Nevis. The next commonest species recovered was Chrysosporium indicum, represented by 15 (13.9%) isolates from St. Kitts and seven (12.7%) isolates from Nevis. Other infrequently isolated keratinophilic species included Chrysosporium tropicum, Chrysosporium keratinophilum, and unidentified Chrysosporium species. This study is the first of its kind in the islands of St. Kitts and Nevis. A high incidence of M. gypseum complex in the soil of these islands is a noteworthy finding of public health significance.

First Description of Onychomycosis Caused by Chrysosporium keratinophilum in Captive Bennett's Wallabies (Macropus rufogriseus rufogriseus)

Seven Bennett's wallabies (Macropus rufogriseus rufogriseus) presented within a period of several months with onychodystrophy, onychomadesis, and severe digital tumefaction. Histopathologic findings included a pseudocarcinomatous hyperplasia of the claw matrix surrounding a cavity filled with keratin and septate hyphae stained with periodic acid Schiff reagent. The fungal species Chrysosporium keratinophilum was identified on cultures. The wallabies were orally treated with ketoconazole (15 mg/kg s.i.d.) for 20 wk. Material and enclosures were cleaned and sprayed with 0.2% enilconazole solution once a month over a period of 4 mo. No improvement of advanced cases was observed, but no new case appeared for the next 6 mo. The positive mycological culture and the invasion of tissues on histopathologic examination suggested that the fungal species C. keratinophilum was implicated in this claw disease. This is the first report of onychomycosis caused by C. keratinophilum in animals.

Keratinophilic fungi on feathers of common clinically healthy birds in Bahrain

The occurrence of keratinophilic fungi associated with feather samples from 10 bird species was investigated using Mycobiotic Agar(®) following the incubation at 25 ± 2°C for 4 weeks. A total of 225 feather samples were cultured, of which 157 (69.77%) were found to be positive. Altogether 184 fungal isolates represented by 11 species and grouped into five genera were recovered viz. Chrysosporium, Trichophyton, Arthroderma, Scopulariopsis and Sepedonium. Based on relative density values to rank species prevalence, the most common genus was Chrysosporium. Chrysosporium keratinophilum was the predominant species (54.34%) on most of the bird species, followed by Chrysosporium tropicum (17.93%). Relative densities of less than 10% were noticed with Chrysosporium merdarium (8.69%), followed by Scopulariosis spp. (7.06%). The lowest density of occurrence was depicted by Arthroderma tuberculatum (0.54%) and Sepedonium spp. (0.54%). Alexandrian parrots and chickens yielded the widest keratinophilic species diversity (6), followed by quail, duck and pigeons (5), while lovebirds showed the narrowest species diversity (1). The average number of species spectra and isolates per bird is 3.7 and 18.4, respectively. The study further showed that apparently healthy bird feathers can harbour a variety of fungi that may be considered as a source for transmitting potential pathogens of clinical importance.

Effect of Chrysosporium keratinophilum metabolites against Culex quinquefasciatus after chromatographic purification

Chrysosporium keratinophilum is known to be a keratinophilic fungus and an effective mosquito control agent. This fungus was grown on Sabauraud dextrose broth in the laboratory at 25°C, while the relative humidity was maintained at 75 ± 5% for 15 days. Filtration process of metabolites was done using whatman-1 filter paper, column chromatography and flash, chromatography. Larvicidal efficacy was performed against all instars of Culex quinquefasciatus. Larvicidal efficacy was performed at six different concentrations with different effective ratios (ethanol/metabolites: 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, and 1:9). The mortality values were then subjected by the probit analysis. The larval mortalities were observed for a period of 24, 48, and 72 h, respectively. The first and second instars were highly susceptible to 2:8 ratio. In the first instar after column chromatography, LC(50) =26.66 ppm, LC(90) =121.96 ppm, LC(99) =231.86 ppm were observed after 72 h, while after flash chromatography the LC(50) =20 ppm, LC(90) =123.02 ppm, LC(99) =281.83 ppm were observed after 48 h. In the second instar after column chromatography, LC(50) =18.19 ppm, LC(90) =102.32 ppm, LC(99) =162.18 ppm were observed after 72 h, while doing flash chromatography 100% mortality could be recorded after 24 h. In the third instar after column chromatography, the LC(50) =38.01 ppm, LC(90) =131.82 ppm, LC(99) =245.47 ppm were observed after 72 h, while after flash chromatography the LC(50) =17.78 ppm, LC(90) =100 ppm, LC(99) =151.35 ppm. In the fourth instar, LC(50) =61.65 ppm, LC(90) =181.97 ppm, LC(99) =436.51 ppm, while after flash chromatography LC(50) =40 ppm, LC(90) =120 ppm, and LC(99) =223.87 ppm were observed after 72 h. The extracellular metabolites of C. keratinophilum could be a fungal based larvicides resource for the control of C. quinquefasciatus larvae. This could be another agent for biotechnological exploitation, if found suitable in field trials.

Survey on the role of brown hares (Lepus europaeus, Pallas 1778) as carriers of zoonotic dermatophytes

The occurrence of dermatophytes and keratinophilic fungi was investigated by hairbrush technique on the coat of 986 apparently healthy brown hares (Lepus europaeus, Pallas 1778) caught in 9 restocking and capture zones in Central Italy. Overall, 7.5% hair samples gave positive results. Trichophyton terrestre (2.1%), Chrysosporium sp, Chrysosporium keratinophilum, Microsporum gypseum, Trichophyton gloriae and Trichophyton mentagrophytes (0.6% each), Trichophyton erinacei and Scopulariopsis brevicaulis (0.4% each), Chrysosporium asperatum (0.3%), Arthroderma sp and Microsporum canis (0.1% each) were identified in cultures with single isolates, whereas Chrysosporium sp/T. mentagrophytes (0.3%), Chrysosporium sp/T. terrestre and M. gypseum/T. terrestre (0.2% each), Chrysosporium tropicum/T. terrestre, M. canis/T. terrestre and T. ajelloi/T. terrestre (0.1% each) were identified in cultures with mixed isolates. T. erinacei and M. canis have not previously been isolated from hares. M. canis, T. erinacei and T. mentagrophytes were the most clinically important dermatophytes found. Altogether, they were isolated only from 1.5% hair samples. Thus, it is concluded that brown hares may play a limited epidemiological role as carriers of zoonotic dermatophytes.Nevertheless, this should be taken into consideration as many people may be exposed to zoonotic agents from brown hares during hunting and trapping activities.

Antagonism of Microsporum species by soil fungi

Eighteen fungi isolated from soil by hair bating method were tested against soil inhabiting Microsporum equinum, Microsporum fulvum, Microsporum gypseum and Microsporum racemosum for their antagonistic interactions. Colony inhibition during dual cultures showed inhibition of all the four Microsporum species. The maximum inhibition of M. equinum, M. fulvum, M. gypseum and M. racemosum was caused by Chrysosporium keratinophilum, Chrysosporium tropicum, Curvularia lunata and Chrysosporium lucknowense in dual cultures. On the other hand, M. fulvum showed maximum inhibition of Macrophomina phaseolina (70.1%) while M. equinum, M. gypseum and M. racemosum showed maximum inhibition of Colletotrichum gloeosporoides. Staling products of C. lucknowense accelerated growth of all Microsporum species, C. keratinophilum 3 and Chrysosporium evolceaunui and M. phaseolina accelerated growth of two species of Microsporum. Staling product of Alternaria alternata was most inhibitory. Culture filtrates of Trichophyton vanbreseughemii accelerated the growth of all the four Microsporum species and C. tropicum, C. lucknowense accelerated growth of two species, while Botryotrichum piluliferum accelerated growth of three species of Microsporum. Volatiles showed inhibition of all the Microsporum species ranging from 0.33 to 57.2% except in case of M. fulvum. Lysis of Microsporum mycelium was the most common feature.

Dermatophytes and other keratinophilic fungi from coypus (Myocastor coypus) and brown rats (Rattus norvegicus)

The occurrence of mycotic agents was investigated by hair-brush technique on the coat of 162 naturalized coypus (Myocastor coypus) and 64 indigenous brown rats (Rattus norvegicus) originating from the same protected area in Central Italy. The isolates from positive coypus (29.6%) were identified as Microsporum gypseum (14.8%), Trichophyton terrestre (9.8%), Alternaria sp. (3.7%), Trichophyton mentagrophytes (2.5%), Cladosporium sp. (1.8%), Scopulariopsis sp. (1.2%), and Chrysosporium keratinophilum (0.6%), whereas the isolates from positive rats (46.7%) were identified as M. gypseum (28.1%), T. mentagrophytes (12.5%), Chrysosporium tropicum and T. terrestre (3.1% each), and Chrysosporium inops (1.6%). Statistically, brown rats were more likely to harbor fungal agents (P < 0.05) on their coat than coypus, especially T. mentagrophytes (P < 0.01) and M. gypseum (P < 0.05). No positive animal showed dermatological lesions. The present results are the first providing basic information on the coat’s mycoflora of a wild coypu population. It is concluded that the coypu, an allochthonous rodent in Italy, can play a role as natural animal reservoir of dermatophytes and as carrier of keratinophilic and saprophytic fungi within its new habitat, though to a lesser extent than indigenous rats. Therefore, people who are exposed to the risk of contact with the coat of rats and coypus should take all the cautions needed to protect themselves from mycotic agents potentially transmissible to humans.

Secretion of keratinolytic enzymes and keratinolysis byScopulariopsis brevicaulisandTrichophyton mentagrophytes: regression analysis

A survey on keratinophilic fungi from poultry-farm soils at Namakkal and from feather dumping soils at Chennai, India, revealed the existence of 34 species of fungi. Most of the fungi exhibited variable efficiency in producing extracellular keratinase when grown in plates with chicken feathers as the sole carbon and nitrogen source. The fungi Aspergillus flavus, Aspergillus niger, Aspergillus versicolor, Chrysosporium state of Arthroderma tuberculatum, Paecilomyces carneus, Scopulariopsis brevicaulis, Trichoderma viride, and Trichophyton mentagrophytes were efficient candidates to degrade the feathers. However, when cultivating the strains in submerged conditions in a medium containing chicken feathers as the sole nutrients source, Aspergillus glaucus, Chrysosporium keratinophilum, Curvularia lunata, Fusarium solani, and Penicillium citrinum also proved to be potent. Among all species, S. brevicaulis and Trichophyton mentagrophytes produced higher amounts of keratinase in both methods. Conditions for keratinase production were optimized by statistical design and surface plots. The highest keratinase activity was estimated by S. brevicaulis (3.2 KU/mL) and Trichophyton mentagrophytes (2.7 KU/mL) in the culture medium with chicken feathers and shows (79% and 72.2% of degrading ability, respectively).

Influence of peptone, ammonia water and urea supplements on keratinolytic and associated non-keratinolytic fungi in sewage sludge

A hair-baiting method was used in laboratory study of the influence on the composition of the keratinolytic and non-keratinolytic mycobiota in sewage of adding the ammonium nitrogen sources, peptone, ammonia water and urea. It was demonstrated that, independent of the nitrogen source, the ammonium nitrogen concentration was the critical factor affecting the fungal composition. Ammonium prevented or markedly inhibited the growth of Trichophyton terrestre , with its teleomorph Arthroderma quadrifidum ; other geophilic dermatophytes and non-keratinolytic fungi. It also favoured growth of Chrysosporium keratinophilum and some other species, mainly in the genus Chrysosporium . The composition of the keratinolytic mycobiota can be an indicator of sludge organic matter stabilization, and used in relation to sewage sludge at wastewater treatment plants and in reclamation practice.

SEASONAL BEHAVIOUR OF KERATINOPHILIC FUNGI ISOLATED FROM PARKS SOIL IN MILAN

Soil samples collected from 10 parks in Milan were examined for the presence of keratinophilic fungi by the Orr’s hair baiting technique. The organisms isolated and their frequency were as follows: Arthroderma uncinatum and its anamorph Keratinomyces ajelloi were dominant and recovered from 22.5% - 43.7% and 40% - 50% of the soil samples collected in summer and winter respectively. Myceliophthora vellerea was isolated in 31.2% of the samples, particularly in winter, Microsporum gypseum in winter (20%) and Trichophyton terrestre (10%) in summer. Chrysosporium keratinophilum (16.2% in summer and 18.7% in winter) C. indicum (15% s- 23.7% w), C. pannicola (5% s - 37% w). Aphanoascus fulvescens was isolated in summer (23.7%). Among the cycloheximide-resistant keratinophilic fungi Alternaria alternata (27.5% s – 33.7% w), Paecilomyces lilacinus (26.2% s - 18.7% w) and Acremonium strictum (8.7% s - 20% w) also were observed. The distribution of the different species is discussed.

Keratinophilic fungi isolated from hospital dust and soils of public places at Gulbarga, India

Keratinophilic fungi were isolated from corridor dust of 11 hospitals and soils of 21 public places using a hair baiting technique. A total of 41 species belonging to 24 genera were recovered. Among the dermatophytes and related species, Microsporum gypseum was predominant, followed by Chrysosporium keratinophilum, Trichophyton mentagrophytes, M. nanum and Ch. tropicum. Other species were represented by 32 species belonging to 21 genera. Most of the species isolated are known to be agents of human and animal infection or have been isolated from human and animal lesions. The fungi observed here are discussed in relation to their global distribution.

Keratinophilic fungi of poultry farm and feather dumping soil in Tamil Nadu, India

Soils of 10 poultry farms from Namakkal and 12 feather dumping sites from Chennai were studied for the presence of keratinophilic fungi. A total of 34 species belonging to 19 genera and one non-sporulating fungus were recovered. Sixteen species of fungi and one non-sporulating fungi were common to both sites, eight species were specific to Namakkal and nine species were specific to Chennai. Dermatophytes and closely related fungi were represented by six species belonging to five genera. Fungal species commonly found in the soil samples included Chrysosporium keratinophilum (73%), Trichophyton mentagrophytes (68.2%), Microsporum gypseum (64%), Myceliopthora vellerea (32%), Chrysosporium state of Arthroderma tuberculatum (27.3%) and Geomyces pannorum (23%). Non-dermatophyte fungi were represented by 28 species belonging to 14 genera and one non-sporulating fungus.

Optimization of an extracellular protease of Chrysosporium keratinophilum and its potential in bioremediation of keratinic wastes.

Chrysosporium keratinophilum IMI 338142 isolated from a waste site containing organopollutants was studied for its ability to produce extracellular proteases on glucose-gelatin medium. Fungus was observed to be a potent producer of such enzymes. Enzyme secretion was best at 15 days of incubation period at pH 8 and temperature 40 degrees C. Asparagine was repressive to protease expression. No relationship existed between the enzyme yield and increase in biomass. Exogenous sugars suppressed enzyme production in the descending order as follows: glucose > arabinose > maltose > mannose > fructose. The enzyme released showed the ability to decompose two keratin substrates tested. Buffalo skin was the most actively degraded substrate when exogenous glucose was absent. Presence of glucose suppressed both enzyme production and degradation of keratin. However, the rate of keratin degradation was independent of enzyme production.