Is induction of the exocellular lipase of Xanthomonas maltophila NK7 by fats and detergents simply the result of continual detachment from the cell surface?

The synthesis and release of the extracellular lipase of Xanthomonas NK7 grown in rich media was maltophila induced by non-substrates of the lipase: hexadecane, the non-hydrolysable detergents, Brij-35 and Triton X-100, and by oleic acid just as efficiently as by the triacylglycerols and hydrolysable detergents normally used to increase lipase yields. It is suggested that induction is the response to physical stripping by absorption of the lipase to micelles and emulsified droplets rather than to a metabolic effect. This view is supported by the following observations: (i) the longer chain triacylglycerols were better inducers than short chain triacylglycerols although they are hydrolysed more slowly by X. lipase; (ii) the yield of lipase increased with the concentration of maltophila olive oil and oleic acid well beyond the concentration which saturated the uptake system, as judged by the disappearance of oil from the medium.