Agri Kultuur January / January 2018 - Page 42

the lipopeptide molecules to produce a standardised and consistent biofungicide on a laboratory scale , which would be effective in a wide range of physical and chemical environments ,” says Prof . Clarke .
The study set out to :
• identify and quantify the key performance indicators for optimal antifungal lipopeptide production ;
• identify and quantify appropriate antifungal lipopeptide concentration and purification procedures ; and
• evaluate the effectiveness of different lipopeptides in various grades of purity on phytopathogens targeting the fruit industry .
Method
The team applied chemical engineering and life science principles to produce , extract , purify and fractionate a cocktail from Bacillus cultures that contained approximately 100 homologues of the lipopeptide families surfactin , iturin and fengycin .
Bacillus spp . culture in
shake flasks .
Supernatant after centrifugation .
Precipitation of lipopeptides caused by adding acid .
Identify and quantify the key performance indicators for optimal antifungal lipopeptide production :
Firstly , a kinetic analysis was conducted to determine the parameters for producing the antifungal lipopeptides surfactin , iturin and fengycin from B . amyloliquefaciens under the most efficient conditions in both shake flasks and laboratory scale bioreactors .
The lipopeptide concentration , yield , productivity and selectivity with changes in oxygen , and nitrate and ammonia ratios and concentrations , were closely monitored .
Findings : The team determined the nitrate and ammonia ratio and concentration for optimal kinetics , in terms of lipopeptide concentration , yield , productivity and selectivity , during the production process . They also found that lipopeptide production is enhanced in the presence of oxygen .
LEARNING ABOUT LIPOPEPTIDES
Antimicrobial lipopeptides are natural antifungal agents found widely in nature . They kill various types of bacteria , fungi and viruses by drilling a hole in the membrane of the microbe and then inactivating and destroying the organism by disrupting transport across the membrane .
Because they primarily disrupt the cell membrane , they are effective against a broad spectrum of pathogenic microorganisms , with less probability of resistance .
Lipopeptide precipitate to be sent for separation and drying .
The antibiotic compounds released by Bacillus spp . are considered one of the most effective biological control mechanisms for plant pathogens . However , when the entire bacterial culture – which is a living organism – is applied directly , the successful release of the antibiotic compounds depends on near-perfect climatic conditions . Such dependency limits use on a commercial scale and prompted research into ways to extract the compounds and make them available without Nature ’ s intervention .
AgriKultuur | AgriCulture
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the lipopeptide molecules to produce a standardised and consistent biofungicide on a laboratory scale, which would be effective in a wide range of physical and chemical environments,” says Prof. Clarke. The study set out to: • identify and quantify the key performance indicators for optimal antifungal lipopeptide production; • identify and quantify appropriate antifungal lipopeptide concentration and purification procedures; and • evaluate the effectiveness of different lipopeptides in various grades of purity on phytopathogens targeting the fruit industry. Method The team applied chemical engineering and life science principles to produce, extract, purify and fractionate a cocktail from Bacillus cultures that contained approximately 100 homologues of the lipopeptide families surfactin, iturin and fengycin. Bacillus spp. culture in shake flasks. Supernatant Precipitation after centrif- of lipopep- ugation. tides caused by adding acid. Identify and quantify the key performance indicators for optimal antifungal lipopeptide production: Firstly, a kinetic analysis was conducted to determine the parameters for producing the antifungal lipopeptides surfactin, iturin and fengycin from B. amyloliquefaciens under the most efficient conditions in both shake flasks and laboratory scale bioreactors. The lipopeptide concentration, yield, productivity and selectivity with changes in oxygen, and nitrate and ammonia ratios and concentrations, were closely monitored. Findings: The team determined the nitrate and ammonia ratio and concentration for optimal kinetics, in terms of lipopeptide concentration, yield, productivity and selectivity, during the production process. They also found that lipopeptide production is enhanced in the presence of oxygen. LEARNING ABOUT LIPOPEPTIDES Antimicrobial lipopeptides are natural antifungal agents found widely in nature. They kill various types of bacteria, fungi and viruses by drilling a hole in the membrane of the microbe and then inactivating and destroying the organism by disrupting transport across the membrane. Because they primarily disrupt the cell membrane, they are effective against a broad spectrum of pathogenic microorganisms, with less probability of resistance. Lipopeptide precipitate to be sent for sepa- r ][ۈ[Z[˂YܚR[]\YܚP[\BH[X[X\[[X\YHKB[\ \HۜY\YۙHوH[YX]H[X[۝YX[\\܂[][ˈ]\[H[\BX\X[[\H8$X\H][ܙ[B\H8$\\YY\XKHX\ٝ[[X\HوH[X[X\[KB[ۈX\\\X[X]Xۙ][ۜ˂X\[[H[Z]\HۈH[Y\BX[[H[\Y\X\[^\^XH\[[XZH[B]Z[XH]]]\x&\[\[[ۋ