| A strain of Penicillium sp. PT95 was isolated from soil sample collected close to Fenyang, Shanxi Province. The strain can form abundant sclerotia in which β -carotene is accumulated. By morphological observation and RAPD typing, the taxonomy position of PT95 strain and biosystematics of it and its close relative species was identified. The effects of both various inorganic salts, carbon and nitrogen sources on sclerotia biomass and carotenoid yield in surface cultures of PT95 strain were also studied.1.The colony and microscopic characters of PT95 strain in 4 kinds of media, i.e. Czapek Yeast Extract Agar (CYA), Malt Extract Agar (MEA), 25%Glycerol Nitrate Agar (G25N) and Czapek Agar (CA), were observed respectively. Colonies on CYA for 7d at 25℃ typically 32mm-40 mm diam, radially sulcate or winkled, usually enveloping abundant sclerotia and overlaid by scattered penicillin. Sclerotia, pink, becoming scarlet in age, globose or irregular, about 300μm diam. Conidiogenesis sparse, caesious; pinicilli monoverticillati strictly, conidiophores borne from surface or subsurface hyphae; phialides ampulliform, 8μm-10μm×1.5μm-2.5μm; codidia ellipsoidal, 2. 5μm -3. 0μm long. Usually no germination at 5℃; occasionally germination observed. No growth at 37℃. Based the characters above, PT95 strain was identified to P. thomii series.2.Three kinds of methods (i. e. benzyl choeide method, CTAB method and SDS-CTAB method) were used to extract DNA from eleven strains of Penicillium, The results showed that the benzyl choeide method was able to be used to extract the DNA of those Penicillium strains, and bands resulting from gel electrophoretic separations were very clear. However, both the CTAB and SDS-CTAB methods were only adequate to be used to extract DNA of some strains of Penicillium, and the DNA bands of some strains were clear, but others were not obvious. The effects of both the pH values of extracts and the grinding of mycelia in liquid nitrogen on the result of DNA extracting were also discussed.3. Eleven strains of Penicillium, i.e. PT95 strain and its 4 mutants as well as 6 standard strains bought from Institute of Microbiology, Academia Sinica, have been analyzed for their RAPD genotype. Among 70 arbitrary primers, 13 primers could get enough amplified bands for allstrains. The genetic relationship had been evaluated by similarity cofficient obtained from these profiles. The cluster showed that all strains could be divided into two parts. The first part consisted of PT95 and all strains of Pinicillium thomii series, and the second part was P. chrysogenum, P. roqueforti and P. pinophilum. The genotypic typing of species seems to be related to morphological classification. But PT95 strain differed from all standard strains of P. thomii series in gel electrophoretic separations. According to cluster, PT95 strain could be obviously distinguished from other strains. The result showed that PT95 strain was not any species known of P. thomii series and probably was a new species.4. This study examined the respective effect of various inorganic salts, carbon and nitrogen sources on sclerotia biomass and carotenoid yield in surface cultures of PT95 strain. Among inorganic salts tested, K2HPO4was more essential to the sclerotia formation and carotenogenesis of strain PT9S than KCl, MgSO4 or FeSO4 It was also shown that the combination of K2HPO4, KCl and MgSO4 could produce the best positive cooperation and give the highest sclerotia biomass (782mg/plate) and pigment yield (328μg/plate). All of five carbon sources, i..e. glucose, sucrose, lactose, maltose and soluble starch, could be utilized by the strain PT95, and maltose was the best. Among 8 nitrogen sources, yeast extract favored the sclerotia formation, and peptone favored the pigment accumulation; amine salts and urea were unfavorable to form sclerotia. The medium containing 0.24 g/L -0.48g/L sodium nitrate-nitrogen was effective to both the sclerotia formation and the carotenoid production of strain PT95 when available maltose-carbon c...
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