Biocontrol Activity of the Local Strain of Metschnikowia pulcherrima on Different Postharvest Pathogens

Area of Science:

• Microbiology
• Food Science
• Biotechnology

Background:

• Metschnikowia pulcherrima exhibits significant biocontrol capabilities against diverse microorganisms.
• The efficacy of M. pulcherrima is primarily attributed to its iron-chelating pigment, pulcherrimin.
• The study focuses on M. pulcherrima UMY15, a strain isolated from local vineyards, for its biocontrol potential.

Purpose of the Study:

• To evaluate the biocontrol efficacy of M. pulcherrima UMY15 against common food spoilage molds.
• To assess the yeast's performance on artificial wounds of apples and in grape juice.
• To determine its effectiveness against postharvest pathogens including Penicillium, Aspergillus, Fusarium, and Rhizopus species.

Main Methods:

• In-vitro plate tests were conducted to assess M. pulcherrima UMY15's activity against various mold species.
• Biocontrol assays were performed on artificial apple wounds and in grape juice, involving coinoculation with target molds.
• The study compared the inhibitory effects on different fungal genera, including Penicillium, Aspergillus, Fusarium, and Rhizopus.

Main Results:

• M. pulcherrima UMY15 demonstrated high efficacy against Penicillium roqueforti, P. italicum, P. expansum, and Aspergillus oryzae in in-vitro tests.
• The yeast showed reduced effectiveness against Fusarium sp. and Aspergillus niger in initial biocontrol assays.
• Complete inhibition of spore germination and mycelial growth was observed for A. oryzae, A. parasiticus, and Fusarium sp. on apple wounds.
• M. pulcherrima UMY15 successfully inhibited the growth of multiple pathogens, including Penicillium, Aspergillus, Fusarium, and Rhizopus, in grape juice.

Conclusions:

• M. pulcherrima UMY15 is a potent biocontrol agent against a broad spectrum of food spoilage molds and postharvest pathogens.
• Its application in controlling fungal contamination on fruits like apples and in beverages like grape juice shows significant promise.
• The yeast's biocontrol activity is linked to its ability to inhibit key spoilage microorganisms, offering a sustainable food preservation strategy.