title: Bacteriostatic Mode of Action of Trypsin-Hydrolyzed Palm Kernel Expeller Peptide Against Bacillus cereus.
abstract: Palm kernel expeller (PKE), the by-product derived from the palm kernel oil milling industry, is commonly added to ruminant feed as a source of protein. Recent research has demonstrated that the enzymatically hydrolyzed protein is inhibitory to spore-forming bacteria including Bacillus cereus. The trypsin-hydrolyzed PKE peptide appears to disrupt the membrane integrity and inhibit the intracellular macromolecule metabolism of B. cereus. The addition of the PKE peptide (350 and 700 μg/ml) to B. cereus cultures triggered the efflux of K(+) and caused the depletion of the intracellular ATP. However, no proportional increase in cell's extracellular ATP was observed. Analysis of the biosynthesis of macromolecules demonstrated that RNA was affected by the PKE peptide. Results of this study suggest that the PKE peptide is bacteriostatic interfering with membrane integrity and forming membrane pores permitting the efflux of K(+) and interferes with intracellular biopolymer synthesis.
authors.affiliation: School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia.
authors.forename: Yen Nee
authors.initials: YN
authors.lastname: Tan
authors.affiliation: Department of Food Science, School of Environmental and Biological Sciences, Rutgers University, 65 Dudley Road, New Brunswick, NJ, 08901, USA.
authors.forename: Karl R
authors.initials: KR
authors.lastname: Matthews
authors.affiliation: Department of Plant Biology and Pathology, School of Environmental and Biological Sciences, Rutgers University, 59 Dudley Road, New Brunswick, NJ, 08901, USA.
authors.forename: Rong
authors.initials: R
authors.lastname: Di
authors.affiliation: School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia. mkhan@ukm.my.
authors.forename: Mohd Khan
authors.initials: MK
authors.lastname: Ayob
keywords: Bacillus cereus; Bacteriostatic; Mode of action; Palm kernel expeller peptide; Trypsin