Journal of Microbiology

Research Support, Non-U.S. Gov't

Production of Anti-Helicobacter pylori Metabolite by the Lichen-Forming Fungus Nephromopsis pallescens: Heng Luo , Yoshikazu Yamamoto , Hae-Sook Jeon , Yan Peng Liu , Jae Sung Jung , Young Jin Koh , Jae-Seoun Hur; J. Microbiol. 2011;49(1):66-70. Published online March 3, 2011; DOI: https://doi.org/10.1007/s12275-011-0289-9

Abstract: The present study was conducted to evaluate the antibacterial activity of lichen-forming fungi (LFF) against Helicobacter pylori, and to optimize the culture conditions of LFF for maximum production of natural antibiotics against H. pylori. To accomplish this, a screening assay was first conducted among 19 species of LFF. The extract of Nephromopsis pallescens (KOLRI-040516) exhibited the strongest anti-H. pylori activity. Bioautograghic TLC and HPLC analysis identified usnic acid as the main antibacterial substance produced by N. pallescens. The growth of N. pallescens and production of antibacterial substances produced by the fungus were then investigated under several culture conditions including the culture media, initial medium pHs, incubation temperatures, and the degree of aeration. The results indicated that culture in MY medium with an initial pH of 6.0, a temperature of 15°C and a low degree of aeration supported the largest usnic acid production of the fungus (16.4 μg usnic acid/g dry biomass). Especially, aeration was found to be an important factor that affect both growth and usnic acid production of N. pallescens.

Culture conditions affecting the molecular weight distribution of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) synthesized by alcaligenaes sp. SH-69: Yoon, Joo Seok , Park, Sang Kyu , Kim, Young Baek , Maeng, Hack Young , Rhee, Young Ha; J. Microbiol. 1996;34(3):279-283.

Abstract: The weight average molecular weight of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) synthesized by Alcaligenes sp. SH-69 was altered between 3.2 × 10^5 and 1.1 × 10^6 depending upon various culture conditions. It appeared that culture conditions favorable for the efficient production of copolyesters promoted the formation of higher molecular weight copolyesters. Polydispersity indices of isolated copolyesters were in the range of 1.5 to 2.5.

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