Figure 2 : Diagram showing the upstream production and downstream recovery , isolation and purification of lipopeptide and purification of lipopeptides
Bacillus spp .
UPSTREAM
Growing the Bacillus bacterial culture on a carbon-rich substrate eg . glucose
Centrifugation of culture
Bacillus cells
MEng students , Sebenzile Mazibuko ( right ) and Willem Herbst .
assess the efficacy of antifungal lipopeptides . The antifungal lipopeptides from B . amylolique faciens as a 10x concentrate were effective against all tested phytopathogens , except A . sclerotiorum .
Conclusion
The bacterially produced bioproducts have considerable potential as an effective and environmentally friendly alternative for the post-harvest control of fungal diseases in crops , either as a multi-product cocktail or as individual fractions , tailor-made for specific plant diseases . The fact that the producing organism has GRAS ( generally regarded as safe ) status , is a considerable advantage .
“ We envisage that it is possible to manipulate the lipopeptide homologues to tailor-make a sniper-like fungicide that targets a specific phytopathogen ,” says Prof . Clarke .
DOWNSTREAM
Supernatant ( cell-free lipopeptides )
Partially purified lipopeptide mixtures Acid precipitaton , lyophilisation ( freeze dried ). Determine lipopeptide concentration of percipitates with HPLC
Freeze-dried lipopeptides in crude powder form
Reconstructed lipopeptide solution ( lipopeptide powder solubilised in an alkaline solution )
Purified lipopeptide mixtures Solvent extraction , membrane filtration , adsorption , size exclusion . Lipopeptide concentration determined by TLC
Ultra-pure antifungal lipopeptide biosurfactant RP-HPLC
WHAT IS HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY ( HPLC )?
This is a technique in analytical chemistry used to separate , identify , and quantify each component in a mixture . It relies on pumps to pass a pressurised liquid solvent containing the sample mixture through a column filled with a solid adsorbent material . Each component in the sample interacts slightly differently with the adsorbent material , causing different flow rates for the different components and leading to the separation of the components as they flow out the column .
HPLC has been used for manufacturing ( eg . during the production process of pharmaceutical and biological products ), legal ( eg . detecting performance enhancement drugs in urine ), research ( eg . separating the components of a complex biological sample , or of similar synthetic chemicals from each other ), and medical ( eg . detecting vitamin D levels in blood serum ) purposes .
( Source : Wikipedia )
AgriKultuur | AgriCulture
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