Broad and complex antifungal activity among environmental isolates of lactic acid bacteria

Abstract

More than 1200 isolates of lactic acid bacteria isolated from different environments were screened for antifungal activity in a dualculture agar plate assay. Approximately 10% of the isolates showed inhibitory activity and 4% showed strong activity against the indicator mould Aspergillus fumigatus. The antifungal spectra for 37 isolates with strong activity and five isolates with low or no activity were determined. Several of the strains showed strong inhibitory activity against the moulds A. fumigatus, Aspergillus nidulans, Penicillium commune and Fusarium sporotrichioides, and also against the yeast Rhodotorula mucilaginosa. Penicillium roqueforti and the yeasts Pichia anomala and Kluyveromyces marxianus were not inhibited. Several isolates showed reduced antifungal activity after storage and handling. The majority of the fungal inhibitory isolates were identified by 16S rDNA sequencing as Lactobacillus coryniformis. Lactobacillus plantarum and Pediococcus pentosaceus were also frequently identified among the active isolates. The degree of fungal inhibition was not only related to production of lactic or acetic acid. In addition, antifungal cyclic dipeptides were identified after HPLC separation and several other active fractions were found suggesting a highly complex nature of the antifungal activity.

Biocontrol efficacy ofLactobacillus fermentumYML014 against food spoilage moulds using the tomato puree model

“…Meanwhile, natural preservatives could be an alternative due to disadvantages of pesticides/fungicides and the high cost of production of new chemicals (Laitila et al 2002). In addition, the biopreservative capacity of lactic acid bacteria (LAB) is gaining much attention, due to consumers' demand for reducing the use of chemical preservatives (Magnusson et al 2003). As a result of this, several researchers have exploited antagonistic compounds (such as organic acids, hydrogen peroxide and other antimicrobial compounds such as bacteriocins) produced by LAB which are able to control pathogenic microorganisms and undesirable moulds in food and feed (Messens & De Vugst 2002;Pulido et al 2005).…”

Transcriptomic and morphological profiling of Aspergillus fumigatus Af293 in response to antifungal activity produced by Lactobacillus plantarum 16

“…The number of reports documenting the antifungal activity of LAB has significantly increased during the last decade (Delavenne et al, 2012;Magnusson et al, 2003;Valerio et al, 2009). In addition, information detailing the extensive food-based applications (Baek et al, 2012;Ryan et al, 2008) and identification of the responsible fungal inhibitory compounds (Brosnan et al, 2012;Ström et al, 2002;Yang et al, 2011) has improved.…”

Secretion of Streptomyces tendae antifungal protein 1 by Lactococcus lactis

“…For many years, LAB strain libraries have been screened for antimicrobial activity towards bacterial pathogens, instead of for their antimicrobial activities against yeasts and fungi. Recently, several LAB have been screened for antifungal activity, an attribute that has often been described as a multifactorial trait involving organic acid (11,12) and cyclic dipeptide production (13). However, antifungal activity is often an unstable trait in LAB (14).…”