Antifungal activity investigation of local lactobacillus strain

Rezaei Nasab, S. (2019) Antifungal activity investigation of local lactobacillus strain. Masters thesis, university of zabol.

[img]
Preview
Text
Antifungal activity investigation of local.pdf

Download (222kB) | Preview

Abstract

Control of fungal spoilage is a major concern in food industry. Such corruption, in addition to the significant economic damage caused by contaminants caused by mycotoxins, causes serious problems for human and animal health. The aim of this study was to use lactobacillus plantarum MT.ZH193 and lactobacillus fermentum MT.ZH893, isolated from dairy products, against to Aspergillus flavus PTCC-5006 and Aspergillus parasiticus PTCC-5286. The effects of four factors including pH (5.5, 6, 6.5,7 and 7.5), temperature (30, 35, 40, 45 and 500c), time (0, 24, 48, 72 and 96h) and Supernatant volume (150, 500, 850, 1200 and 1550μl) on inhibition of A. flavus PTCC-5006 and A. parasiticus PTCC-5286 growth were tested by response surface methodology. The optimization of supernatant production conditions, as the novel source of antifungal compounds was performed. The optimization value for pH, temperature, time and Supernatant volume for L. plantarum MT.ZH193 and L. fermentum MT.ZH893 against to A. flavus PTCC-5006 and A. parasiticus PTCC-5286 was 6.73, 350c, 24h, 1200μl ; 6.63, 37.770c, 24h, 1200 μl and 6.79, 350c, 24h, 1200 μl ; 6.87, 350c, 24h, 1200μl respectively. The ability of cell free supernatant, from the optimization step, in inhibition of A. flavus PTCC-5006 and A. parasiticus PTCC-5286 Spore germination and aflatoxin (B1, B2, G1, G2) production has been investigated. The highest percentage of spore germination inhibition belonged to L. plantarum MT.ZH193 against to A. flavus PTCC-5006 (84%). Also the highest percentage reduction in aflatoxin B1, producted by A. parasiticus PTCC-5286 was due to the supernatant from L. plantarum MT.ZH193 (39.87%). volatility test was performed to investigate the synergistic effects of L. plantarum MT.ZH193 and L. fermentum MT.ZH893 on radial growth inhibition of A. flavus PTCC-5006 and A. parasiticus PTCC- 5286. Also the effect of three factors in five levels including time (4, 5, 6, 7 and 8 day), temperature (21.59, 25, 30, 35 and 38.40c), inoculation size (0, 25, 50, 75 and 100) on the radial growth inhibition of A. flavus PTCC-5006 and A. parasiticus PTCC-5286 has been investigated. The optimization value for time, temperature and inoculation size for L. plantarum MT.ZH193 and L. fermentum MT.ZH893 against to A. flavus PTCC-5006 and A. parasiticus PTCC-5286 were 6 days, 30.930c, 58% and 6 days, 31.950c, 58% respectively. Model evaluation under the predicted optimal conditions confirms the validity of the model in predicting the experimental results.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Lactobacillus, Aspergillus, Supernatant, Aflatoxin, Volatile compounds, Antifungal, GC-MS
Subjects: Q Science > QR Microbiology
Depositing User: Mrs najmeh khajeh
Date Deposited: 18 Feb 2020 04:30
Last Modified: 18 Feb 2020 04:30
URI: http://eprints.uoz.ac.ir/id/eprint/2673

Actions (login required)

View Item View Item