Fig. 5

Optimal pH (a), pH stability (b), optimal temperature (c), and thermostability (d) of ReLipA. Optimal pH was determined by measuring the enzyme’s activity at 40 °C in 50 mM of different buffers within pH range of 3.0–9.0. The buffers used were citrate buffer (filled diamond) (pH 3.0–6.0), MES buffer (filled square) (pH 5.5–6.5), phosphate buffer (filled triangle) (pH 6.0–8.0), and Tris–HCl (×) (pH 7.5–9.0). To investigate pH stability, the samples were incubated at 30 °C for 30 min in various buffers mentioned above, and the residual activities were then measured in citrate buffer (pH 6.0) at 30 °C. The optimal temperature was determined at different temperatures (0–60 °C) in 50 mM citrate buffer (pH 6.0). For thermostability determination, the enzyme was incubated in 50 mM citrate buffer (pH 6.0) for 30 min at 30–60 °C prior to enzyme assay