Cultural conditions on the production of extracellular enzymes by Trichoderma isolates from tobacco rhizosphere

Abstract Twelve isolates of Trichoderma spp. isolated from tobacco rhizosphere were evaluated for their ability to produce chitinase and β-1,3-glucanase extracellular hydrolytic enzymes. Isolates ThJt1 and TvHt2, out of 12 isolates, produced maximum activities of chitinase and β-1,3-glucanase, respectively. In vitro production of chitinase and β-1,3-glucanase by isolates ThJt1 and TvHt2 was tested under different cultural conditions. The enzyme activities were significantly influenced by acidic pH and the optimum temperature was 30 °C. The chitin and cell walls of Sclerotium rolfsii, as carbon sources, supported the maximum and significantly higher chitinase activity by both isolates. The chitinase activity of isolate ThJt1 was suppressed significantly by fructose (80.28%), followed by glucose (77.42%), whereas the β-1,3-glucanase activity of ThJt1 and both enzymes of isolate TvHt2 were significantly suppressed by fructose, followed by sucrose. Ammonium nitrate as nitrogen source supported the maximum activity of chitinase in both isolates, whereas urea was a poor nitrogen source. Production of both enzymes by the isolates was significantly influenced by the cultural conditions. Thus, the isolates ThJt1 and TvHt2 showed higher levels of chitinase and β-1,3-glucanase activities and were capable of hydrolyzing the mycelium of S. rolfsii infecting tobacco. These organisms can be used therefore for assessment of their synergism in biomass production and biocontrol efficacy and for their field biocontrol ability against S. rolfsii and Pythium aphanidermatum infecting tobacco.

Preliminary Study on Solid-state Fermentation of Streptomyces Strain Men-myco-93-63 / 微生物学通报

The culture medium and cultural conditions of solid-state fermentation of Streptomyces Menmyco-93-63 were tested in this study. The suitable medium which contains rice, sorghum, millet bran, and rice hull with the proportion of 2:2:3:3 was developed for the spore production of Streptomyces Men-myco-93-63 using single substrate screening, mixture substrate screening and orthogonal experiments, and the sporulation was up to 2.52?109 CFU/g. And then, initial charge, initial ratio of water to solid, inoculating quantity, and culture temperature impact to sporulation of Streptomyces Men-myco-93-63 were tested. The favorite cultural conditions are developed as the following: the initial charge is 15 g in 500 mL Erlenmeyer flask; initial ratio of water to solid is 1.7:1.0 (V/W, rice hull excluding), inoculating quantity is 7 mL, culture temperature is 28℃.

The Optimal Culture Conditions for the Mycelial Growth of Oudemansiella radicata

Oudemansiella radicata, one of edible mushrooms belonging to Tricholomataceae of Basidiomycota, has been known to exhibit outstanding therapeutic effects on the hypertension caused by high blood pressure and inhibitory effects on the sarcoma 180 and Erhrlich carcinoma of mice. As one of preliminary experiments for producing fruiting-body of O. radicata, this study was carried out to obtain the basic information for culture conditions of mycelial growth of the fungus. The optimal temperature and pH for the mycelial growth were 25degrees C and pH 6, respectively. The medium for favorable mycelial growth of O. radicata was shown in the Lilly medium, whereas compact mycelial density was found in Hamada medium. The carbon and nitrogen sources promoting for mycelial growth of O. radicata were xylose and alanine, respectively. The optimum C/N ratio was about 20 : 1 in case that 3% glucose was supplimented to the basal medium as a carbon source.

The Characteristics of Cultural Conditions for the Mycelial Growth of Macrolepiota procera

Macrolepiota procera, one of edible mushrooms belongs to Agaricaceae of Basidiomycota, has a good taste and good medicinal value. As a preliminary study for the development of artificial cultivation method of edible mushroom, cultural characteristics of M. procera was investigated on various culture media under different environmental conditions. Mycelial growth was compared on culture media composed of various carbon and nitrogen sources, and C/N ratios. The optimal conditions for the mycelial growth were 30degrees C and pH 7. M. procera showed the rapid mycelial growth in the PDA media. The optimal carbon and nitrogen sources were maltose and glycine, respectively. The optimum C/N ratio was about 10 : 1 in case that 1% glucose was supplemented to the basal media as carbon source.

Culture Conditions Affecting the Optimal Mycelial Growth of Cystoderma amianthinum

Cystoderma amianthinum, one of edible fungi belongs to Agaricaceae of Basidiomycota, has a good taste and flavor. This study was carried out to obtain the basic informations for the optimum mycelial growth of C. amianthinum. The optimal conditions for the mycelial growth were 25degrees C and pH 5 in potato dextrose agar (PDA). C. amianthinum showed the favorable growth in the PDA and yeast malt extract agar (YMA). The favorable carbon and nitrogen sources promoting mycelial growth were fructose and histidine, respectively. The optimum C/N ratio was about 30 : 1 in case that 1% glucose was supplemented to the basal medium as a carbon source.

The Optimal Culture Conditions Affecting the Mycelial Growth and Fruiting Body Formation of Paecilomyces fumosoroseus

The fruiting body of Paecilomyces fumosoroseus was collected at Mt. Mani, Ganghwa Island, Korea in September, 2001. This study was carried out to obtain the basic informations for the mycelial growth and fruiting body production of P. fumosoroseus in artificial media. The optimal conditions for the mycelial growth were obtained at 25degrees C and in the range of pH 6~9, respectively. P. fumosoroseus showed the favorable growth on Hamada medium. The carbon and nitrogen source favorable for mycelial growth were dextrin and histidine, respectively. Optimum C/N ratio suitable for optimal growth of P. fumosoroseus was observed on the culture media adjusted to the ratio of 40:1. The mycelial growth of P. fumosoroseus was optimal on corn meal agar supplemented with 30% of silkworm pupae. The most favorable fruiting body formation of P. fumosoroseus was obtained in the medium containing unpolished rice supplemented with 20% (w/w) silk worm pupae at 25degrees C under 100 lux.

STUDIES ON PRODUCTION CONDITIONS OF FLOCCULANT FROM PSEUDOMONAS SP.GX_4-1 USING FISH MEAL WASTEWATER / 微生物学通报

The conditions of Pseudomonas sp.GX 4\|1 producing flocculant only using fish meal wastewater were mainly studied.Under the optimum culture conditions:medium COD 10g/L,initial pH 7～9,cultural temperature 30,and the shaking speed,100～250r/min,the flocculating rates can highly reach more than 97% with maxmium 99 5%,even if the culture medium was not sterilized.This flocculant shows high flocculating efficiency to kaolin clay suspension,soil suspension,activate carbon powder suspension and wastewater fromelectroceramics plant.