Journal of Drug Metabolism & Toxicology
Open Access
ISSN: 2157-7609
+44-20-4587-4809
ISSN: 2157-7609
+44-20-4587-4809
Kenneth M Bischoff, Neil P J Price, Timothy D Leathers and Pennapa Manitchotpisit
National Center for Agricultural Utilization Research, USA
Illinois State University, USA
Scientific Tracks Abstracts: J Drug Metab Toxicol
Liamocins are a heterogeneous mixture of polyol-lipids produced by the fungus Aureobasidium pullulans. When grown on sucrose, A. pullulans strain NRRL 50380 produces four types of liamocins with chemical structures consisting of a single mannitol head group partially O-acylated with polyester tails containing three or four 3,5-dihydroxydecanoic ester groups, some of which are acetylated. Liamocins possessed antibacterial activity with specificity against Streptococcus species with MICs ranging from �?¢�?�?�?¤10 �?�?�?¼g/ml to 78 �?�?�?¼g/ml for the following: S. agalactiae, S. infantarius, S. mitis, S. mutans, S. pneumonia, S. salivarius, S. suis and S. uberis. Enterococcus faecalis and Bacillus subtilis were less susceptible, while the following bacteria were not susceptible: Staphylococcus aureus, Lactobacillus fermentum, Escherichia coli and Pseudomonas aeruginosa. In an effort to improve yields (typically 0.5-6.0 g liamocin/L), different growth media and strains of A. pullulans were tested. Selective growth on different polyols resulted in considerable structural variation of liamocins including some with galactitol, sorbitol, D-arabitol, D-xylitol and D- or L-threitol head groups. Liamocins with D-arabitol or D/L-threitol head groups were active but to a lesser extent than the mannitol liamocins. The components of mannitol liamocins were separated by HPLC and assayed by MALDI-TOF/MS, and a fraction that was enriched for liamocin B1 (the non-acetylated type with four 3, 5-dihydroxydecanoic acid groups) had the highest antibacterial activity against S. agalactiae (MIC = 16 �?�?�?¼g/ml). Liamocins have potential application as a narrow spectrum antimicrobial agent that targets streptococcal pathogens, but avoids disruption of normal flora and reduces selection for antibiotic resistance in commensal bacteria.
Kenneth M Bischoff received his PhD in Biochemistry from Purdue University in 1995. He joined the USDA Agricultural Research Service in 1998 as a Microbiologist investigating antimicrobial resistance in food-borne pathogens. In 2004, he relocated to the USDA National Center for Agricultural Utilization Research (NCAUR), Peoria, IL and redirected his research towards improving the biochemical processes for the bio-refining industry. He is currently a lead scientist for bio-based products research in the Renewable Product Technology Research Unit at NCAUR.