Purification of a new antifungal compound produced by Lactobacillus plantarum AF1 isolated from kimchi

The aim of this study was to purify and to identify an antifungal compound of Lactobacillus plantarum AF1, which was isolated from kimchi, and to determine if Lb. plantarum AF1 can prevent fungal growth in a particular food model system. The antifungal compound was purified using SPE and recycling prep-HPLC and its structure was elucidated using NMR and ESI-MS. The active compound from Lb. plantarum AF1 is C12H22N2O2, 3,6-bis(2-methylpropyl)-2,5-piperazinedion has a molecular mass of 226. This is a new antifungal compound produced by lactic acid bacteria (LAB). To investigate the potential application of the antifungal compound to eliminate fungal spoilage in food and feed, soybean was used as a model. White mycelia and dark green spores of Aspergillus flavus ATCC 22546 were observed in the control soybeans after 1 to 2 days incubation. However, fungal growth was not observed in the soybeans treated with a 4-fold concentrated supernatant of Lb. plantarum AF1 culture, even after 2 days. The end products produced from kimchi LAB, like 3,6-bis(2-methylpropyl)-2,5-piperazinedion identified in this study, may be a promising alternative to chemical preservatives as a potential biopreservative which prevent fungal spoilage and mycotoxin formation in food and feed.