Penicillinase (beta-lactamase) formation by blue-green algae

Beta-Lactamase (penicillinase) activity was found in a number of strains of blue-green algea. In some cases, this enzyme permitted algae to overcome the inhibitory effects of penicillin. Production and localization of beta-lactamase were studied in a unicellular species, Coccochloris elabens (strain 7003), and in a filamentous, nitrogen-fixing Anabaena species (strain 7120). When cells were grown in a neutral medium with NaNO3 as N source, the pH rose during growth; at a pH of about 10, most of the enzyme was expressed equally well in intact or disrupted cells. If the pH was kept near neutrality during growth by gassing with CO2 in N2 or by growth under conditions of N2 fixation, the enzyme remained cell-bound and cryptic for most of the growth phase, being measurable only after cells were disrupted. The enzymes from strains 7003 and 7120 had greater activity on benzyl penicillin and other penicillins than on cephalosporins. Some differences were observed in the "substrate proliles" of penicillinases from the two strains against different penicillins.