The potential of non-ionic polysorbate surfactants as alternative inducers of medium-chain-length poly(3-hydroxyalkanoates) (MCL-PHAs) for the production of diverse bacterial MCL-PHA depolymerases was evaluated. When grown with corn oil as the sole carbon substrate, Pseudomonas alcaligenes LB19 preferentially produced lipolytic enzymes, but its MCL-PHA depolymerase was not induced by the substrate. However, the results of activity staining and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis clearly revealed that Tween 20 induced simultaneous production of lipolytic enzymes and the MCL-PHA depolymerase with the molecular mass (26.5 kDa) of P. alcaligenes LB19, which has been previously identified. Moreover, the co-production of two functionally distinct hydrolytic enzymes induced by Tween 20 was commonly observed in various Gram-positive and Gram-negative bacteria that were fed the substrate. Thus, it is expected that non-ionic polysorbate surfactants including Tween 20 can be widely exploited as promising universal substrates for the facile and efficient production of diverse MCL-PHA depolymerases. (C) 2012 Elsevier Ltd. All rights reserved.