Novel Antifungal Compounds, Spermine-Like and Short Cyclic Polylactates, Produced by Lactobacillus harbinensis K.V9.3.1Np in Yogurt

Abstract

Lactobacillus harbinensis K.V9.3.1Np was described as endowed with high antifungal activity. Most of the studies associated this activity to the produced organic acids, i.e., lactic acid, acetic acid, and hexanoic acid. The aim of this study was to purify and identify, other not yet described, antifungal molecules produced by L. harbinensis K.V9.3.1Np when used in yogurt fermentation. Active compounds were extracted through several extraction processes using organic solvents and protein precipitation. The fractions of interest were purified using flash chromatography and preparative HPLC for specific characterization. The bioactive compounds identification was performed using Nuclear Magnetic Resonance and Mass Spectrometry. Activity tests against Penicillium expansum and Yarrowia lipolytica showed that the active compounds from L. harbinensis K.V9.3.1Np are benzoic acid and a polyamine identified as a spermine analog, which has not been reported earlier. However, the highest activity was shown by a mixture of short (n = 2–5) polycyclic lactates. Our overall results demonstrate the efficiency of the proposed extraction/purification approach. The new compounds described here have promising antifungal activities but further studies are still needed to decipher their mode of action and production pathways. Even though, they present an interesting potential application in food, feed, as well as, in pharmaceutical industries and could serve as alternative to chemical additives.

Lactic Acid Bacteria as Antifungal and Anti‐Mycotoxigenic Agents: A Comprehensive Review

“…There has been great progress in understanding and exploring novel antifungal metabolites of LAB during the last few years. Apart from some novel antifungal peptides produced by many LAB species (Gerez, Torres, Font de Valdez, & Rollán, 2013;Luz et al, 2017;McNair et al, 2018;Muhialdin et al, 2016;Muhialdin, Hassan, & Saari, 2018;Rather et al, 2013), many other novel antifungal metabolites of LAB have been reported recently that included 10-hydroxy-12-octadecenoic acid (10-HOE), 13-hydroxy-9-octadecenoic acid (Chen, Liang, Curtis, & Ganzle, 2016), benzeneacetic acid, 2-propenyl ester (Wang, Yan, Wang, Zhang, & Qi, 2012), phenolic antioxidants (such as, 2,4 di-tert-butyl phenol) (Sellamani et al, 2016;Varsha et al, 2015), 2-hydroxy-(4-methylthio) butanoic acid, 2-hydroxy-3-methylbutanoic (Honoré et al, 2016) and spermine-like and short cyclic polylactates (Mosbah et al, 2018). Aunsbjerg et al (2015) reported the role of volatile compounds (diacetyl) produced by Lactobacillus paracasei DGCC 2132 in inhibiting the growth of two fungal species belonging to the genus Penicillium: P. solitum DCS 302 and Penicillium sp.…”

Combined Machine Learning and Molecular Modelling Workflow for the Recognition of Potentially Novel Fungicides

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Predominant Mycotoxins, Pathogenesis, Control Measures, and Detection Methods in Fermented Pastes

“…For instance, both L. plantarum and related low-molecular-weight substances showed significant antifungal activity [70]. Recent research revealed that various novel metabolites of LAB, including 13-hydroxy-9-octadecenoic acid, 10-hydroxy-12-octadecenoic acid [71], phenolic antioxidants [72], and spermine-like and short cyclic polylactates [73], showed lower minimum inhibitory concentrations of mycotoxins compared to the ordinary organic acids. Lactobacillus fermentum YML014 was also shown to reduce A. flavus by up to 50% after isolation from Nigerian fermented food (Cassava) [74].…”