Novel Antibacterial Polypeptide Laparaxin Produced By Lactobacillus Paracasei Strain NRRL B-50314 Via Fermentation

Siqing Liu,Brian J Wilkinson

doi:10.4172/2157-7463.1000121

Abstract

This study reports the production and characterization of a novel antibacterial polypeptide, designated laparaxin, which is secreted by Lactobacillus paracasei NRRL B-50314. Crude laparaxin has antibacterial activity against a wide variety of Gram-positive bacteria, including: lactic acid bacteria (Lactococcus lactis and Lactobacillus buchneri), food-borne pathogens (Listeria monocytogenes), gastrointestinal pathogens (Enterococcus faecalis), and opportunistic pathogens (Staphylococcus aureus methicillin-sensitive (MSSA) and methicillin resistant (MRSA) strains, a hetero-vancomycin-intermediate methicillin resistant strain (Hetero VISA also MRSA) MM66, and homogeneous vancomycin intermediate (Homo VISA). Using L. lactis as an indicator strain, the inhibitory activity of crude laparaxin was detected originally in early log phase, and the activity maximizes at the early stationary phase and remains stable after prolonged incubation. Laparaxin activity is stable after 30 min of incubation at 94°C. Higher concentrations of inhibitory activity are produced when glucose, fructose and sucrose are used as carbon-sources in growth media. Crude laparaxin has potential applications in food and feed industries, as well as in clinical and veterinary medicine.

Highlights

Conventional antibiotics are not degraded, and residues can accumulate in the environment which promotes the emergence of multi-drug resistant strains [1]
We report the production of a biodegradable polypeptide laparaxin by a novel bacterial isolate Lactobacillus paracasei that shows antibacterial activities against several antibiotic resistant Staphylococcus aureus strains
Isolation and identification of bacterial contaminants The L. paracasei strain was isolated from a laboratory culture tube of Lactobacillus buchneri which showed decreased turbidity after 24 hrs compared to other similar L

Summary

Introduction

Conventional antibiotics are not degraded, and residues can accumulate in the environment which promotes the emergence of multi-drug resistant strains [1]. In the fuel ethanol fermentation industry, where fermenting microbes are used to convert biomass sugars to fuels and chemicals, bacterial contamination of the fermentors often lead to down time of the production facilities and increased operational cost [2]. A disadvantage of applying conventional antibiotics is that they do not degrade such that remaining residues may accumulate along the production process and can contribute to the emergence of multi-drug resistant bacterial strains. Bacterial strains with multidrug resistance to virginiamycin and penicillin were reported in dry-grind ethanol plants [3]

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