The effect of agitation rate on lipid utilisation and clavulanic acid production in Streptomyces clavuligerus

Many industrial bioprocesses use complex medium containing both carbohydrate and oils as carbon sources. Oil supplements may lead to increased antibiotic titre and can be a cheaper alternative carbon source compared to carbohydrates. The major disadvantage to the use of oils in the process medium is the level of oil remaining at the end of the process. Research has been undertaken to examine the effects of stirrer speed on lipid utilisation and clavulanic acid production in 5-l batch cultivation of Streptomyces clavuligerus. Increasing tip speed from 1.88 to 2.83 m s −1 improved biomass production while 3.77 m s −1 was detrimental to growth. Lipase activity decreased with increasing stirrer speeds. An optimum tip speed was found for clavulanic acid production. Tip speed did not significantly alter the rate of lipid utilisation or the total lipid remaining at the end of the process.