ANTIFUNGAL ACTIVITIES OF ETHYL ACETATE FRACTION OF PSEUDOMONAS FLUORESCENS FERMENTATION BROTH AGAINST PHYTO-PATHOGENIC FUNGI FROM ROTTEN YAM
ANTIFUNGAL ACTIVITIES OF ETHYL ACETATE FRACTION OF PSEUDOMONAS FLUORESCENS FERMENTATION BROTH AGAINST PHYTO-PATHOGENIC FUNGI FROM ROTTEN YAM
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Date
2018-08
Authors
UMAR, Rashida Danladi
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Abstract
Yam tubers are prone to infestation by microorganism at all stages of growth and in storage. This rot reduces the quality of yam and affects food security. Pseudomonas fluorescens possess varieties of promising antifungal properties through production of secondary metabolites which makes it a biocontrol agent against many phyto-pathogens. In this study, the antifungal activities of metabolite produced by Pseudomonas fluorescens isolated in Zaria was evaluated. Rhizosphere soil was collected from different farms (sugarcane, rice and soybeans) in Zaria, Nigeria and Pseudomonas fluorescens was isolated and identified in accordance with standard microbiological procedure using cultural, microscopical and biochemical characteristics. The four isolate obtained were grown in three (3) fermentation media made from waste such as yam peel, banana peel and sugarcane shaft as carbon sources and groundnut cake as nitrogen source. Crude extract from these fermentations were tested for antifungal activities against Aspergillus niger, Penicillium citrinum, and Rhizopus stolonifer isolated from rotten yam using agar diffusion assay. Only four isolates labelled sugarcane A1, sugarcane A2, Rice B1 and Rice B2 were identified as Pseudomonas fluorescens and only fermentation broth extracts of Sugarcane A2, Rice B1 and Rice B2 had remarkable antifungal activities against the fungi with diameter zones of inhibition ranging from 14.00 – 39.00mm in two (2) of the fermentation media. The crude extracts from P. fluorescens fermentation broth were extracted in this study and were observed to inhibit the mycelial growth of the test fungi with zone of inhibition ranging from 19.50 - 33.50mm. The in vitro & in vivo MICs showed significant antifungal activities against test fungi spores. Rhizopus stolonifer was observed to be the most susceptible test organism in vitro & in vivo (0.15 – 5.00mg/ml). This study showed that the Pseudomonas fluorescens isolated in Zaria produced potential antifungal metabolite which can arrest the growth of phyto-pathogenic fungi associated with yam tubers.
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A THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY, ZARIA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF A MASTER OF SCIENCE DEGREE (M.Sc.) IN PHARMACEUTICAL MICROBIOLOGY. DEPARTMENT OF PHARMACEUTICS AND PHARMACEUTICAL MICROBIOLOGY, FACULTY OF PHARMACEUTICAL SCIENCES, AHMADU BELLO UNIVERSITY, ZARIA, NIGERIA
Keywords
ANTIFUNGAL ACTIVITIES,, ETHYL ACETATE FRACTION, PSEUDOMONAS FLUORESCENS,, FERMENTATION,, PHYTO-PATHOGENIC FUNGI,, ROTTEN YAM,