Fig. 3

Screening of selected representatives for lipolytic activity. a Strains containing empty vector (empty pCC) serving as negative control and expressing Lipase A from Bacillus subtilis serving as positive control, as well as representatives for families FUMEFAM011958 (GOS54), FUMEFAM010194 (GOS55), FUMEFAM018084 (GOS88), and FUMEFAM012527 (GOS89) were cultivated on LB agar plates containing 1% tributyrin. Clear halos around the colonies indicate lipolytic activity. b The same strains on agar plates containing 1% triolein and 0.001% rhodamin B. Colonies show orange fluorescence under UV light in the presence of lipolytic activity. All plates were incubated for 2 days at 37 °C. c-d Lipolytic activity of crude extracts from these strains. 4 biological replicates were tested. Crude extract of E. coli expressing lipase A from Bacillus subtilis was set to 100% activity. c Crude extract of strains expressing GOS54 was three times more active against pNP-butyrate than lipase A. d In contrast, GOS54 was less active against pNP-palmitate as substrate. e Substrate conversion over time was measured continuously over 20 min at 405 nm. E. coli with empty pCC vector served as a negative control (grey line). Heterologously expressed lipase A from B. subtilis served as positive control (dashed line). Substrate was added as indicated by an arrow. GOS54 hydrolyzes both pNP-butyrate and pNP-palmitate, but prefers the shorter chain-length substrate