Figure 4

Acetaldehyde-induced colouration of microbial lipases in toluene (A) and in the presence of different buffer components (B). A) Lipases from C. rugosa (Sigma type VII, CRL), P. fluorescens (Amano AK, PFL), R. oryzae (Amano F-AP15, ROL), BSL-A, and BSL-B were lyophilized from buffer adjusted to pH = 10 and incubated in the presence (+) or absence (-) of 500 mM acetaldehyde in toluene. B) Influence of acetaldehyde (500 mM), NaOH (10 mM), and glycine (10 mM) on colour of solutions (upper row), solubilized (middle row) and precipitated (lower row) BSA (1 mg/mL). Therefore, water or BSA in water was incubated with (+) or without (-) acetaldehyde and the buffer components glycine and NaOH. Subsequently, all samples containing BSA were treated with TCA to document the colour of the protein pellet (BSA in water after TCA-precipitation).