Phylogenetic Analysis Of Fusarium Species From Vegetable Fruits

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Date
2014-07
Authors
Zambry, Nor Syafirah
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Publisher
Universiti Sains Malaysia
Abstract
The present study focused on screening and evaluating extracellular biosurfactant production from 33 actinomycete isolates. Out of 33 isolates, isolate R1, characterized as the genus Streptomyces based on phenotypic and genotypic analyses, was selected as a model filamentous organism in an aerobic fermentation for biosurfactant production. The production of biosurfactant was investigated in batch mode using shake flasks and 3 L stirred tank bioreactor. The maximum biosurfactant production in shake flasks with reduction in surface tension of water (39.37±1.73%) and emulsification activity (20.69±4.88%) was obtained at 144 hours in a medium containing 6% (v/v) palm oil, 0.6% (w/v) yeast extract, 2% (v/v) Tween 80, 0.7% (w/v) NaCl and initial pH 6 with 4% (v/v) inoculum concentration. Further improvement in the biosurfactant production was achieved using a well-controlled stirred tank reactor. An increase of 3-fold of emulsification activity and lowest surface tension measurement (40.5±0.05 dynes/cm) was attained when the culture was agitated at 600 rpm. In batch cultures, the production of biosurfactant was not dependent on biomass but was influenced by culture morphology. Solvent extraction method using methanol, chloroform and 1-butanol (1:1:1) gave the highest concentration (58.04 g/L) of crude biosurfactant extract that was characterized as glycolipid biosurfactant. The glycolipid biosurfactant produced by Streptomyces sp. R1 is able to reduce the surface tension of water from 74±0.58 to 38 dynes/cm with a critical micelle concentration (CMC) of 10% (v/v) biosurfactant spent broth. It was found stable over a wide range of temperature, pH and salinity.
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Keywords
Phylogenetic analysis of , Fusarium species
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