Selection of pectinolytic fungi for degumming of natural fibers

Summary Polygalacturonase (PG), total pectinase (TP) and cellulase were determined by species ofAspergillus, Humicola andPenicillium and the best producers of pectinase enzymes were isolates ofP. versicolor followed byP. expansum, A. niger, anotherP. versicolor andA. fumigatus.     

青霉属的三个新种

本文报导青霉属的三个新种,它们不同于此属已发表的诸种.异型青霉(Penicillium heteromorphum Kong et Qi),根据帚状枝的结构和分生孢子的某些特征,近于两型孢青霉(Penicillium dimorphosporum Swart),但此种在查氏琼脂上生长很稀疏,并有两种大小的分生孢子,大分生孢子直径可达10 pm,壁光滑,在观察菌落期间,有时大分生孢子落在基质上,很快萌发生长成简单的分生孢子结构,这些特征易于与后者区分.结节青霉(Penicillium nodulum Kong et Qi)在某些方面类似纠缠青霉(Penicilliumimplicatum Biourge),此新种的菌落特征,柄顶端膨大似顶囊,呈结节状膨大的营养菌丝等特征而不同于纠缠青霉.神农架青霉(Penicillium shennong jianum Kong et Qi)和毡毛青霉(Penicillium velutinum van Heyma)相近,而新种在多种培养基上生长都局限,菌落面呈带褐的橄榄色,分生孢子壁光滑等特征可与毡毛青霉区分开来.     

Sequential actions of pectinases and cellulases during secretory cavity formation in Citrus fruits

Pectinase and cellulase activities are involved in a number of intercellular space-forming processes in plants. In this study, we combined cytochemistry with ultrastructural analysis to investigate the ontogeny of secretory cavity in fruits of Citrus medica L. var. sarcodactylis (Noot.) Swingle, Citrus reticulata Blanco and Citrus limon (L.) Burm. f. Pectinase activity was first detectable at the initial stage of cavity formation, peaked at the intercellular space-forming stage, and diminished at the following stages. In comparison, no cellulase activity was detected until the early lumen-expanding stage. The cellulase activity increased at the late lumen-expanding stage and culminated at the near-mature stage. In the fruit of C. medica var. sarcodactylis, the distribution of pectinase and cellulase reaction products was restricted to the endoplasmic reticulum (ER), the vesicles derived from ER and the cell wall. We also observed that multivesicular structure containing the pectinase reaction product at the initial stage of cavity formation. Our results suggest that pectinase and cellulase are synthesized on ER and secreted directly into the cell wall through exocytosis of ER-derived vesicles. Our observations are consistent with the notion that the secretory cavity in Citrus fruits is formed through a schizolysigenous process in which pectinase activity is involved in the degradation of the middle lamella, whereas cellulase activity is responsible for the degradation of the cell wall.     

Antagonism against Rhizoctonia solani and fungitoxic metabolite production by some Penicillium isolates

A number of Penicillium isolates were recovered in association to Rhizoctonia solani strains pathogenic on tobacco and from soil on plates pre-colonized by the pathogen itself. Their antagonism toward R. solaniAG-2-1 was evaluated in dual cultures in vitro. Inhibition of growth was evident to some extent in most pairings, while hyphal interactions referable to mycoparasitic relationships were not observed. However, the occurrence of plasmolysis and/or vacuolisation and the induction of monilioid cells were indicative of the release of bioactive compounds. Therefore, production of fungitoxic metabolites was tested by adding concentrated culture filtrates of each Penicillium isolate to the growth medium of R. solani. Complete and lasting inhibition was incited by culture filtrates of some isolates belonging to P. brevicompactum, P. expansum, and P. pinophilum. Three purified compounds, respectively mycophenolic acid, patulin and 3-O-methylfunicone, which were extracted from culture filtrates, were able to inhibit R. solani in vitro. Their production was also detected in dual cultures of the same Penicilliumstrains with R. solani prepared in sterilized soil and when the Penicilliumstrains were cultured directly on R. solani mycelium harvested from liquid cultures. The possible role of such metabolites in antagonism of the above-mentioned Penicilliumspecies against R. solani is discussed.     

Penicillium Mycobiota in Arctic Subglacial Ice

Fungi have been only rarely isolated from glacial ice in extremely cold polar regions and were in these cases considered as random, long-term preserved Aeolian deposits. Fungal presence has so far not been investigated in polar subglacial ice, a recently discovered extreme habitat reported to be inhabited exclusively by heterotrophic bacteria. In this study we report on the very high occurrence (up to 9000 CFU L⁻¹) and diversity of filamentous Penicillium spp. in the sediment-rich subglacial ice of three different polythermal Arctic glaciers (Svalbard, Norway). The dominant species was P. crustosum, representing on the average half of all isolated strains from all three glaciers. The other most frequently isolated species were P. bialowiezense, P. chrysogenum, P. thomii, P. solitum, P. palitans, P. echinulatum, P. polonicum, P. commune, P. discolor, P. expansum, and new Penicillium species (sp. 1). Twelve more Penicillium species were occasionally isolated. The fungi isolated produced consistent profiles of secondary metabolites, not different from the same Penicillium species from other habitats. This is the first report on the presence of large populations of Penicillium spp. in subglacial sediment-rich ice.     

Exocellular hydrolases from Penicillium ulaiense

Penicillium ulaiense exhibited carboxymethylcellulase, pectinase, protease, amylase and phenolase activities, while no xylanase, cellulase, lipase or ligninase activities were found. Pectinolytic action was studied in liquid medium, showing low levels of pectinesterase and pectinase production. No mycotoxins were detected by thin-layer-chromatography.The authors are with INIQUI, Universidad Nacional de Salta, Buenos Aires 177, 4400 Salta, Argentina     

Enzymatic production of N-acetyl- -glucosamine from chitin. Degradation study of N-acetylchitooligosaccharide and the effect of mixing of crude enzymes

N-Acetyl- -glucosamine (GlcNAc) was produced from chitin by use of crude enzyme preparations. The efficient production of GlcNAc by cellulases derived from Trichoderma viride (T) and Acremonium cellulolyticus (A) was observed by HPLC analysis compared to lipase, hemicellulase, and pectinase. β-Chitin showed higher degradability than α-chitin when using cellulase T. The optimum pH of cellulase T was 4.0 on the hydrolysis of β-chitin. The yield of GlcNAc was enhanced by mixing of cellulase T and A.     

A new role for veratryl alcohol: regulation of synthesis of lignocellulose-degrading enzymes in the ligninolytic ascomyceteous fungus, Botryosphaeria sp.; influence of carbon source

A new physiological role for veratryl alcohol in fungi important in the biodegradation of the lignified plant cell wall is presented. Botryosphaeria sp., grown on starch, pectin, cellulose or xylan produced amylase, pectinase, cellulase, xylanase and laccase, whereas glucose and xylose repressed the synthesis of cellulase and xylanase, but not laccase. When cultured on each of these substrates in the presence of veratryl alcohol, laccase activity increased but the activities of amylase, pectinase, cellulase and xylanase significantly decreased. Basal medium containing softwood kraft lignin in the presence of veratryl alcohol induced laccases above constitutive levels. Ethyl alcohol also stimulated laccase production.     

A report on Penicillium in the intramural and extramural air of residential areas of Nagpur city (India)

Prevalence of different species of Penicillium and their concentrations per cubic meter of air were evaluated with the use of Hi-Air sampler system Mark II (Hi-Media Laboratories Ltd., India) in the air of homes (bed-rooms) at four different sites in Nagpur. At each of these sites, air sampling was done fortnightly in triplicate for 2 years duration from June 2000 to May 2002. The sampling was also done in triplicate for the outdoor air in the vicinity of each home on the same day immediately after the indoor sampling was over. The mean concentration of Penicillium colony forming units at four different sites in the indoor air was 32, 46.9, 35 and 35.4 CFU/m³, respectively, whereas in the outdoor air at these same four sites, the mean concentration was 24, 28, 25 and 25.8 CFU/m³ respectively. The Penicillium concentration in the indoor air was found to be higher in winter than in other seasons (ANOVA, p < 0.05). Concentration of Penicillium spp. in intramural environment was always higher than that in extramural environment. Statistically significant difference existed between intramural and extramural environments at all the sites, with maximum difference at a site, which is old crowded area of the city. During the 2-years investigations, 11 species of Penicillium were isolated from the indoor air while nine species were isolated from the air outside the homes. The dominant species of Penicillium in indoor as well as outdoor air were P. citrinum (33.78 and 32.81), P. oxalicum (19.70 and 22.60), and P. chrysogenum (17.64 and 14.50). The percentage of the Penicillium in the indoor air was 10.70 while it was 8.36 in outdoor air. Indoor air showed the presence of P. glaber and P. sclerotiorum, which were absent in the outdoor air.     

Phosphate solubilization by Penicillium spp. isolated from soil samples of Indian Himalayan region

A total of 246 fungal isolates representing 36 genera and 72 species were isolated from the soil samples collected from Indian Himalayan region. Twenty-one species belonged to the genus Penicillium alone. All the Penicillium species were screened for phosphate solubilizing activity on Pikovskaya agar at 21 °C. Eight species of Penicillium, exhibiting formation of halos (zone of solubilization) around the fungal colonies in qualitative plate assays, were selected for quantitative estimations. In quantitative estimations that were conducted upto day 30 (at 3 days interval), seven species of Penicillium brought maximum solubilization after day 15, while P. oxalicum showed maximum solubilization after day 21 of incubation. The increase in solubilization coincided with decrease in pH of the broth. Acid phosphatase activity was 1.5–2.0 times higher in comparison to alkaline phosphatase. Many of these species showed wide range of tolerance for temperature, pH and salt concentration.     

A report on <Emphasis Type="Italic">Penicillium</Emphasis> in the intramural and extramural air of residential areas of Nagpur city (India)

Prevalence of different species of Penicillium and their concentrations per cubic meter of air were evaluated with the use of Hi-Air sampler system Mark II (Hi-Media Laboratories Ltd., India) in the air of homes (bed-rooms) at four different sites in Nagpur. At each of these sites, air sampling was done fortnightly in triplicate for 2 years duration from June 2000 to May 2002. The sampling was also done in triplicate for the outdoor air in the vicinity of each home on the same day immediately after the indoor sampling was over. The mean concentration of Penicillium colony forming units at four different sites in the indoor air was 32, 46.9, 35 and 35.4 CFU/m³, respectively, whereas in the outdoor air at these same four sites, the mean concentration was 24, 28, 25 and 25.8 CFU/m³ respectively. The Penicillium concentration in the indoor air was found to be higher in winter than in other seasons (ANOVA, p < 0.05). Concentration of Penicillium spp. in intramural environment was always higher than that in extramural environment. Statistically significant difference existed between intramural and extramural environments at all the sites, with maximum difference at a site, which is old crowded area of the city. During the 2-years investigations, 11 species of Penicillium were isolated from the indoor air while nine species were isolated from the air outside the homes. The dominant species of Penicillium in indoor as well as outdoor air were P. citrinum (33.78 and 32.81), P. oxalicum (19.70 and 22.60), and P. chrysogenum (17.64 and 14.50). The percentage of the Penicillium in the indoor air was 10.70 while it was 8.36 in outdoor air. Indoor air showed the presence of P. glaber and P. sclerotiorum, which were absent in the outdoor air.     

柚子皮黑曲霉的分离鉴定及产酶特性研究

对柚子皮上自然生长的黑曲霉进行分离鉴定,并探讨其产酶特性。以平板稀释法从柚子皮上分离出一株霉菌菌株,通过观察其形态特征和培养特征,对照《真菌鉴定手册》判定该菌株的种属;采用鉴定培养基法对其产酶特性进行分析。根据柚子皮的成分特性,以干柚子皮为主要原料,该菌为生产菌株,采用固态发酵法探究培养基的成分、柚子皮含量、培养基初始含水量及发酵时间4个因素对纤维素酶活力的影响。结果表明,该菌株为黑曲霉(Aspergillus nige),可产淀粉酶、蛋白酶、纤维素酶、果胶酶;固态发酵培养基中添加柚子皮12g,麸皮0.5 g和(NH_4)_2SO_40.5 g,培养基初始含水量保持在68.5 mL/100 g,培养时间控制在60 h左右时纤维素酶产量较高。     

Allergenic and mutagenic characterization of 14 <Emphasis Type="Italic">Penicillium</Emphasis> species

Extracts of 14 Penicillium species, P. aurantiogriseum, P. brevicompactum, P. citrinum, P. chrysogenum, P. expansum, P. glabrum, P. hirsutum, P. italicum, P. janthinellum, P. melini, P. oxalicum, P. purpurescens, P. simplicissimum, and P. viridicatum were investigated by total protein, specific enzyme determinations, isoelectric focusing (IEF), sodium dodecylsulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting using pooled human atopic IgE. Considerable variation was observed between the Penicillium species with respect to protein yield and the number of distinct protein bands resolved in IEF. Using the Api-Zym system, the most common activities observed among the extracts included acid and alkaline phosphatase, phosphodiamidase and β-glucosaminidase. The number of discrete atopic IgE-reactive bands in immunoblots of Penicillium extracts ranged from 1 (P. chrysogenum) to 9 (P. viridicatum). Certain allergens showed potential for cross-reactivity between species, including 52 and 54 kDa proteins in P. citrinum, P. purpurescens, P. viridicatum and 40 kDa proteins in several species. The extracts were also nonmutagenic when tested with the Ames assay using Salmonella strains TA98 and TA100. The results tend to indicate that P. viridicatum, P. janthinellum, P. oxalicum, P. brevicompactum and P. italicum, which are highly immunogenic as well as allergenic, could possibly be good candidates for allergen cloning studies through the construction of cDNA libraries. The extracts were non-mutagenic and can be used safely for skin testing.*Presented in part at the 7th International meeting of Aerobiology, Montebello, August, 2002.     

Identification of different species ofPenicillium causing deterioration of the Moroccan table grapes during storage

Penicillium glabrum, P. purpurescens, P. decumbens, P. expansum, P. chrysogenum, P. crustosum andP. aurantiogriseum are responsible for some of the alterations noticed on Moroccan table grapes cold stored. Contamination of these table grapes withPenicillium species occurs in the vineyard and inside the cooling station where other fruits which are often fungus-contaminated are also kept. All of thesePenicillium species were able to grow at 0°C apart fromP. glabrum andP. purpurescens. Consequently, refrigeration of grapes during long-term storage is not sufficient in itself in preserving their initial qualities.     

Dominant fungi in the rhizosphere of established tea bushes and their interaction with the dominant bacteria under in situ conditions

Species of Penicillium and Trichoderma were found to dominate the rhizosphere of established tea bushes in a detailed study conducted from various tea growing locations in India. Penicillium erythromellis, P. janthinellum, P. raistrickii, Trichoderma pseudokoningii and T. koningii were found to be closely associated with tea roots. While seasonal fluctuation was observed in the case of Penicillium spp., the population of Trichoderma spp. showed less variation during the year. Both species were sensitive to low temperatures. In general, fungi associated with the tea rhizosphere were found to prefer a mesophillic temperature range (15 °C to 35 °C). The dominant species of Penicillium and Trichoderma also exhibited tolerance to lower temperatures, i.e., 5 to 10 °C on agar plates. Most fungi were able to grow in a wide range of pH (4 to 12). Lowering of soil pH in the rhizosphere of tea bushes was positively correlated with the age of the bush and may have affected the development of a specific microbial community in the rhizosphere.The populations of Penicillium and Trichoderma species were inversely correlated with the populations of two most dominant rhizosphere bacteria, Bacillus subtilis and B. mycoides. Both Bacillus species have been shown to have antagonistic activity against these two fungi under in vitro conditions. The present study demonstrates the existence of a similar antagonism under in situ conditions in the rhizosphere of established tea bushes.     

NephrotoxigenicPenicillium species occurring on farm-stored cereal grains in western Canada

The incidence of nephrotoxigenicPenicillium species on farm-stored cereals in western Canada was determined by morphological and metabolite profile examination. Of the 142 isolates examined 102 were toxin producers with 61P. aurantiogriseum and 27P. freii. Other nephrotoxigenic species includedP. tricolor (6 isolates),P. verrucosum Chemotype II (4 isolates) andP. viridicatum Westling (4 isolates). The nephrotoxigenicPenicillium species profile for western Canada appears to differ from that of Denmark whereP. verrucosum,P. cyclopium,P. freii and, to a lesser extent,P. aurantiogriseum,P. polonicum, andP. viridicatum predominate.     

Penicillium andAspergillus species in the habitats of allergy patients in the Tulsa, Oklahoma area

Penicillium andAspergillus have been recognized as important aeroallergens for more than 30 years, and are especially significant in indoor environments. There are over 400 species ofPenicillium andAspergillus combined, but there is little information on which species occur most frequently in the environment, or if each exhibits unique allergenic properties. A preliminary study showed no overlap between those species isolated from an outdoor site in Tulsa, Oklahoma and the species used in immunotherapy at allergy clinics in the Tulsa area. Pursuing this line of research, air samples were collected as three seasonal samples (over a 6 month period) in the homes or offices of ten allergy patients known to be allergic toPenicillium and/orAspergillus. Twenty three species ofPenicillium and 12 species ofAspergillus were identified from these samples through isolation, macroscopic, and microscopic examination.Penicillium corylophilum, P. glabrum, Aspergillus niger, andA. flavipes were the most abundant species isolated, supporting the data obtained in a preliminary study. At least in the Tulsa area, it appears that atopic patients are being tested and treated with extracts ofPenicillium andAspergillus species that are either not present or not abundant in the local indoor or outdoor environments. Additional research is necessary to determine if the environmental isolates share allergens with those species used in immunotherapy.     

Nephrotoxicity of Penicillium aurantiogriseum and P. commune from an endemic nephropathy area of Yugoslavia

Seven out of nine Penicillium isolates from mouldy maize in Yugoslavia have been differentiated into the adjacent species P. aurantiogriseum and P. commune. Nephrotoxicity of cultured mycelia in the rat has been demonstrated for all isolates of both species and was correlated usefully, though indirectly, with the production of benzodiazepine secondary metabolites, notably auranthine. Shredded wheat (22 g) moulded by an example of each species and fed to a rat over 4 days elicited renal pathology in the P₃ segment of proximal tubules, involving frequent pyknosis and extensive mitosis typical of this as yet uncharacterised toxin. The effect was attributed in P. aurantiogriseum at least partly to the spores. Prominent pathology was elicited by only lg of spores given over 4 days.     

Cellulase production and activity in a species ofCladosporium

ACladosporium species produced large amounts of cellulase enzyme components when grown in shake-culture with medium containing carboxymethylcellulose. There was significantly less activity when Avicel, filter paper or cotton were used as substrates. KNO₃ was better than NH₄Cl or urea for the production of cellulase. Tween 80 at 0.1% (w/v) increased the production of cellulase by 1.5 to 4.5-fold. All the cellulase components were optimally active in the assay at pH 5.0 and 60°C.     

Hydrolysis of cellulose derived from steam exploded bagasse by Penicillium cellulases: Comparison with commercial cellulase

A complete cellulase from Penicillium pinophilum was evaluated for the hydrolysis of α-cellulose derived from steam exploded sugarcane bagasse and other cellulosic substrates. α-Cellulose at 1% substrate concentration was completely hydrolyzed by Penicillium cellulase within 3 h wherein at 10% the hydrolysis was 100% within 24 h with an enzyme loading of 10 FPU/g. The hydrolysate yielded glucose as major end product as analyzed by HPLC. Under similar conditions, hydrolysis of Sigmacell (microcrystalline cellulose), CP-123 (pulverized cellulose powder) and ball milled Solka Floc were 42%, 56% and 52%, respectively. Further the hydrolysis performance of Penicillium sp. cellulase is compared with Trichoderma reesei cellulase (Accellerase^TM 1000) from Genencore. The kinetics of hydrolysis with respect to enzyme and substrate concentration will be presented.