Recombinant Lactococcus lactis strains based on the P170 expression system were developed for hyaluronan (HA) production, by incorporating genes from the has operon of Streptococcus zooepidemicus and compared with nisin-inducible recombinant L. lactis strains containing the hasABC and hasABD constructs. It was found across all batch and fed-batch experimental studies that HA concentration and molecular weight (MW) were higher for the P170 expression systems than the corresponding NICE-based strains. The highest hyaluronan MW was obtained for all constructs in batch studies at 60. g/L initial glucose concentration, the highest being 2.94. MDa for the P170 strains with hasABC construct (L. lactis APJ3). In fed-batch studies with constant feed rate, the L. lactis APJ3 gave better HA yield (0.03. g/g) than the NICE-based strain. A higher hyaluronan MW was obtained for all strains in pulse fed-batch compared to constant feed experiments, the highest being 2.52. MDa for L. lactis APJ3. © 2014 Elsevier B.V.