Effect of culture medium composition on the activity of extracellular lectins of Lentinus edodes

The time course of lectin production in culture liquid of the basidial fungus Lentinus edodes strain F-249 in different media under the conditions of submerged culture was studied. The activity of agglutinins depended on the ratio between carbon and nitrogen sources and pH of culture medium. The activity of lectin in culture medium was maximal when the fungus was grown in a medium containing L-arabinose as a source of carbon and L-asparagine as a source of nitrogen (C : N ratio, (9.5-12): 1)) on the day 15-18 of culturing at pH 8-9.     

Effects of carbon and nitrogen sources,carbon-to-nitrogen ratio,and initial pH on the growth of nematophagous fungus <Emphasis Type="Italic">Pochonia chlamydosporia</Emphasis> in liquid culture

The effects of carbon and nitrogen sources, carbon-to-nitrogen ratio (C:N) and initial pH value on the growth and sporulation of the nematophagous fungus Pochonia chlamydosporia in liquid culture were examined. Among the 21 carbon sources and 15 nitrogen compounds tested, the optimal carbon and nitrogen sources for mycelial growth were sweet potato and L-tyrosine, and for sporulation were sweet potato and casein peptone. A C:N ratio of 10:1 at pH 3.7 gave the maximum yield of conidia and a C:N ratio of 40:1 at pH 6.8 gave the maximum biomass. The initial pH value had a significant effect on mycelial growth and conidial production, with the optimal ranges being 3.5–4.5 for sporulation and 5–6 for growth. Maximum conidial production was obtained at an initial pH of 4.0 and the maximum biomass at pH 6.0. The results also showed that the final pH after 7 days cultivation was always higher than the initial value. The variability in growth and sporulation of seven strains of P. chlamydosporia in liquid culture was also compared and discussed.     

Polysaccharides of <Emphasis Type="Italic">Ganoderma lucidum</Emphasis>: Factors affecting their production

The conditions of polysaccharide production by the fungus Ganoderma lucidum were optimized. The maximal yield of endopolysaccharides and exopolysaccharides was observed at 25–30°C, initial pH of culture medium 4.0–6.0, and at a C:N ratio of 18:1 and 25:1, respectively. The greatest yield of mycelium was reached at a more intensive aeration, and the maximal yield of polysaccharides was observed at a less intensive aeration. The optimal ratio between fungus growth and polysaccharide production was observed at 100 rpm and an aeration of 1.0– 1.5 1/1 medium·min.Translated from Prikladnaya Biokhimiya i Mikrobiologiya, Vol. 41, No. 2, 2005, pp. 194–199.Original Russian Text Copyright © 2005 by Babitskaya, Shcherba, Puchkova, Smirnov.     

A thermostable lipase produced by a newly isolated <Emphasis Type="Italic">Geotrichum</Emphasis>-like strain,R59

Growth and production of lipase by a new Geotrichum-like strain, R59, were studied. Production of extracellular lipase was substantially enhanced when the initial pH of the culture medium, types of carbon and nitrogen sources, substances probably stimulating the lipase biosynthesis, the temperature, and time of growth were optimized. Sucrose and triolein were the most effective carbon sources for lipase production. Maximum lipase activity (146 U/ml^–1) was obtained with urea as the nitrogen source. Growth at 30°C, an initial pH of 6.0 and incubation time of 48 h were found as optimum conditions for cell growth and production of lipase by Geotrichum-like strain R59. The enzyme was thermostable and exhibited very high activity after 1 h incubation at 60°C.     

Production and characterization of extracellular lipase from Calvatia gigantea

Summary A number of factors affecting production of extracellular lipase by the edible fungus Calvatia gigantea were investigated. Consecutive optimization of carbon and nitrogen sources, initial pH of culture medium and growth temperature resulted in an increase in lipase activity of 87%. Under optimum conditions, activities as high as 22.4 units ml^–1 of culture medium were obtained, competing favourably with most activities reported for other lipase hyperproducing microorganisms. The enzyme was optimally active at pH 7.0 and 30°C and had, at optimum pH, half-lives of 75.7 and 22.9 min at 45 and 55°C. Both high activity and kinetic characteristics of the enzyme make this process worthy of further investigation.Correspondence to: B. J. Macris     

Semi-defined Medium for in vitro Cultivation of the Fastidious Insect Pathogenic Fungus Cordyceps unilateralis

Cordyceps unilateralis is a fastidious fungal pathogen affecting ants. Up to now, only the complex and expensive Grace’s insect cell culture medium has been used for in vitro cultivation (as blastospores and mycelium) of this fungus. To obtain an inexpensive and less complicated medium, the effects of carbon and nitrogen sources, salt solution and carbon-to-nitrogen (C:N) ratio on the growth of this fungus were examined. Glucose was the most important factor for blastospore formation, and yeast extract could be used as a nitrogen source for blastospore formation and mycelial growth. A suitable C:N ratio (glucose: yeast extract) was 33.3:1. As a result, a new semi-defined medium was achieved, composed of 26.68 g L⁻¹ glucose, 3.3 g L⁻¹ yeast extract and salt solution. This medium supported blastospore formation and mycelial growth of all tested C. unilateralis isolates.     

Production of Penicillin G acylase from Bacillus sp.: Effect of medium components

A Bacillus sp. producing a high level of intracellular penicillin G acylase (PAC) was isolated. The PAC production in this strain was induced by phenylacetic acid. Various carbon and nitrogen sources were evaluated for their effect on growth and PAC production at 28 °C and pH 7.0. Cells grown in medium supplemented with sucrose as carbon source and tryptone as nitrogen source produced maximum activity of 6.45 and 8.92 U mg^–1, respectively. Maximum concentration of PAC (10.1 Umg^–1) was produced by the cells grown in the medium containing sucrose and tryptone, which was twofold higher than the production in basal medium.     

Carbon and nitrogen requirements of Fusarium oxysporum causing cotton wilt

Summary The present work was carried out to study the nutritional requirements of the cotton wilt-inducing fungus, i.e.Fusarium oxysporum on a synthetic liquid medium with regard to the carbon and nitrogen sources at varying concentrations in terms of the average mycelial dry weights.The optimum carbon requirements of the fungus ranged from 7000–8000 p.p.m. irrespective of the carbon source used in experiment. Carbon utilization was best on sucrose followed by maltose, starch, glucose, fructose and cellulose successively.The optimum nitrogen requirements of the fungus were 300 p.p.m. of nitrogen in the medium; nitrogen utilization was best on using nitrate-nitrogen followed by glycine, glutamic acid, ammonium nitrate, asparagine and ammonium sulphate.Maximum growth of the fungus took place on media containing a C/N ratio ranging between 22.8 and 25.7.Colour formation is correlated with varying either source or concentration of nitrogen and not carbon.     

Interactions in a mixed culture composed of Cellulomonas flavigena and Xanthomonas sp. growing in continuous culture on sugar cane bagasse

A mixed culture formed by Cellulomonas flavigen and Xanthomonas sp. was able to grow in continuous culture in a medium with sugar cane bagasses as carbon source without additional growth factors. The effect of temperature, pH and dilution rate (D) upon the microbial population ratio and biomass composition was studied. Both microorganisms co-existed between 30 and 40° C, at pH 5.8–7.0 and D = 0.04–0.11 h^–1. Correspondence to: T. Ponce-Noyola     

Production of peroxidase by Inonotus weirii

Summary The white rot fungus Inonotus weirii produced an extracellular peroxidase which was excreted in association with cell growth and in the absence of an inducer. Production of peroxidase was greatly influenced by the carbon and nitrogen source. The highest activities were obtained on glucose-and xylose-based media containing a combination of ammonium nitrate, yeast extract and distiller's spent grain as nitrogen source. The enzyme produced had a molecular weight of 42000, was stable in the pH range 3–8 at room temperature and had optimal activity at pH 3. The fungus Inonotus weirii could be a potential producer of peroxidase for industrial applications in spite of its rather slow production rate.     

Repeated-batch production of kojic acid in a cell-retention fermenter using Aspergillus oryzae M3B9

A cell-retention fermenter was used for the pilot-scale production of kojic acid using an improved strain of Aspergillus oryzae in repeated-batch fermentations. Among the various carbon and nitrogen sources used, sucrose and yeast extract promoted pellet morphology of fungi and higher kojic acid production. Repeated-batch culture using a medium replacement ratio of 75% gave a productivity of 5.3 g L^–1 day^–1 after 11.5 days of cultivation. While batch culture in shake-flasks resulted in a productivity of 5.1 g L^–1 day^–1, a productivity of 5 g L^–1 day^–1 was obtained in a pilot-scale fermenter. By converting the batch culture into repeated batches, the non-productive downtime of cleaning, filling and sterilizing the fermenter between each batch were eliminated, thereby increasing the kojic acid productivity.     

Simultaneous biodegradation ofp-cresol and phenol by the basidiomycetePhanerochaete chrysosporium

Summary The fungusPhanerochaete chrysoporium BKM-F-1767 was able to degrade high concentrations ofp-cresol (up to 150 mg L^–1) provided that glucose was added as a carbon and energy source and conditions favourable to ligninolytic enzyme activities were used, i.e. a nitrogen-limited medium. The fungus also simultaneously degradedp-cresol (50 mg L^–1) and phenol (50 mg L^–1) in a mixture at similar rates. Kinetics ofp-cresol biodegradation were almost identical whether the compound was tested individually or in a mixture with phenol.     

Evaluation of a new fungus <Emphasis Type="Italic">Ceriporia lacerate</Emphasis> strain P2—its ability to decolorize Alizarin Red and Methyl Orange

A new fungus Ceriporia lacerate P2 which belongs to family Polyporaceae was evaluated for its ability to decolorize two different dyes Alizarin Red and Methyl Orange. Different parameters such as incubation time, pH, carbon source, nitrogen source and carbon/nitrogen regimes were used to find out the optimum medium for Ceriporia lacerate P2 on its ability of decolorization. The results show that the fungus had different ability to decolorize the two tested dyes. For Alizarin Red, the most suitable medium was at pH 3 and the best carbon and nitrogen source were sucrose and ammonium nitrate. While for Methyl Orange, the optimum medium was at pH 7–9 and the best carbon and nitrogen source were sucrose and urea.     

Optimization of medium composition and culture conditions for agarase production by Agarivorans albus YKW-34

Effect of medium composition and culture conditions on agarase production by Agarivorans albus YKW-34 was investigated in shake flasks. The most suitable carbon source, nitrogen source, and culture temperature were agar, yeast extract, and 25 °C, respectively, for agarase production by one-factor-at-a-time design. The nutritional components of the medium and culture conditions were analyzed by Plackett–Burman design. Among the nine factors studied, agar, yeast extract, and initial pH had significant effects on agarase production (p < 0.05). The optimum levels of these key variables were further determined using a central composite design. The highest agarase production was obtained in the medium consisting of 0.23% agar and 0.27% yeast extract at initial pH 7.81. The whole optimization strategy enhanced the agarase production from 0.23 U/ml to 0.87 U/ml. The economic medium composition and culture condition as well as the dominant occupation of agarase with high activity in culture fluid enlighten the potential application of A. albus YKW-34 for the production of agarase.     

Erratum to: Extracellular protein production and morphogenesis of <Emphasis Type="Italic">Lentinula edodes</Emphasis> in submerged culture

Along with a brief review of Lentinula edodes (shiitake mushroom) submerged cultivation history within the framework of important extracellular proteins biosynthesis, this study contains the authors’ own results. The possibility of regulating the lectin activity of shiitake using the synthetic components is shown. The time course of lectin production in culture liquid of L. edodes in different media under submerged culture conditions was studied. The activity of agglutinins depended on the ratio between carbon and nitrogen sources and the pH of the culture medium. A relationship between the chemical composition of nutrient medium, the activity of extracellular lectins of L. edodes, and the formation of pigmented mycelial film in liquid culture has been found. The formulation of medium, on which the brown mycelial film appears in several days of submerged cultivation, is proposed. The results obtained make a contribution to the present notion of biochemical processes that give rise to the occurrence of the aforesaid morphological structure of shiitake. Finally, two extracellular lectins from the submerged culture of L. edodes have been isolated and purified to homogeneity. Their physicochemical properties and composition have been studied.     

Production of medium chain length polyhydroxyalkanoates by fed-batch culture of Pseudomonas oleovorans

Pseudomonas oleovorans was cultivated to produce medium chain length polyhydroxyalkanoates (MCL-PHAs) from octanoic acid and ammonium nitrate as carbon and nitrogen source, respectively, by a pH-stat fed-batch culture technique. The octanoate in the culture broth was maintained below 4 g l^–1 by feeding the mixture of octanoic acid and ammonium nitrate when the culture pH rose above 7.1. The final cell concentrations of 63, 55 and 9.5 g l^–1, PHA contents of 62, 75 and 67% of dry cell wt, and productivities of 1, 0.63 and 0.16 g l^–1 h^–1 were obtained when the C/N ratios in the feed were 10, 20 and 100 g octanoic acid g^–1 ammonium nitrate, respectively.     

Carbon and Nitrogen Source Nutrition of Fumagillin Biosynthesis by <Emphasis Type="Italic">Aspergillus fumigatus</Emphasis>

The carbon and nitrogen source requirements of Aspergillus fumigatus NRRL 2436 for growth and production of the angiogenesis inhibitor fumagillin were studied in chemically defined media. Both carbon and nitrogen sources strongly influenced fumagillin formation. Two out of 29 carbon sources tested interfered with fumagillin biosynthesis. The best combination of two carbon sources was 30 g L⁻¹ xylan and 50 g L⁻¹ mannose. Of fifteen nitrogen sources tested, three ammonium salts (chloride, sulfate, and dibasic phosphate) failed to support fumagillin formation, presumably due to the low pH which developed. The dosage-response study of the best nitrogen source, L-glutamic acid, revealed that 9 g L⁻¹ was optimal. Volumetric production of fumagillin was increased by 15-fold over that in the starting (Peterson-Goldstein) medium as a result of these findings. Received: 8 April 2002 / Accepted: 24 June 2002     

Removal of carboxymethyl cellulase activity from the culture filtrate of Termitomyces clypeatus producing xylanase

Termitomyces clypeatus produced 450 IU xylanase ml^–1 in a medium containing starch-free wheat bran powder as the carbon source. Carboxymethyl cellulase (CMCase) activity in the culture filtrate was removed by keeping the filtrate at pH 10 for 60 min followed by a change to pH 6. Treatment of Kraft pulp (bamboo) with the filtrate at pH 7 decreased the kappa number from 10.5 to 5 with release of reducing groups equivalent to 0.15 mg glucose g^–1 pulp.     

N2-fixation in Erwinia herbicola

Four from 18 strains of Erwinia herbicola tested had nitrogenase activity and grew with N₂ as sole source of nitrogen under strict anaerobic conditions with a doubling time of 20–24 h. Nitrogenase activity started only 96–120 h after transfer to a special medium maintained under anaerobic conditions. A ten fold increase in protein per culture found after the maximum nitrogenase activity of 80–130 nmol C₂H₄. mg protein^-1·min^-1 was accompanied by a fall in pH of the medium (20 mM phosphate buffer and in 125 mM Tris-buffer) from pH 7.2 to 5.4 or less, but only to 6.8 in 100 mM phosphate buffer. In all cases we found a sharp curtailing of nitrogenase activity 48 h after the maximum. The bacteria utilized only 35–50% of the nitrogen fixed for growth. Erwinia herbicola strains differed from two strains of Enterobacter agglomerans in being unable to fix nitrogen on agar surfaces exposed to air. Specific nitrogenase activity in Erwinia herbicola is compared with data reported for other Enterobacteriaceae and is found to be higher than that reported for Klebsiella pneumoniae, Enterobacter cloacae or Citrobacter freundii.     

Interrelationships between carbohydrate metabolism and nitrogen assimilation in cultured plant cells

Summary The effect of the nature and concentration of the nitrogen source on respiratory activity and removal of carbohydrate from the medium in suspension cultured sycamore (Acer pseudoplatanus L.) cells was determined. Comparison was also made of the rates of uptake of the two alternative nitrogen sources, nitrate and glutamate, at differing initial nitrogen concentrations within the range 7–14 mM. The initial pH of the culture medium before inoculation was 5.2; after inoculation the pH of both nitrate and glutamate cultures rose to reach an eventual level in the range 7.0–7.1. Glutamate was removed from the medium more slowly than nitrate. Under the particular conditions of culture used the growth of the cells was nitrogen limited. Sugar uptake from the medium continued for some time after the nitrogen in the medium was depleted. The data show that although cell division and protein content are nitrogen-limited, dry weight and fresh weight yields may also be determined in a complex interaction through carbohydrate availability. There were no obvious differences in respiratory activity between cultures grown on nitrate or glutamate.