Characterisation of the lipolytic enzymatic activities of fungal rizoenzymes from Rhizopus oryzae in comparison to pancreatin from pigs

In case of exocrine pancreatic insufficiency (EPI), the replacement of digestive enzymes with, for example porcine pancreatin or fungal rizoenzymes, is unavoidable under certain conditions. Current guidelines indicate that preparations from porcine pancreas have more advantageous physicochemical properties compared to those from fungi, especially at high bile salt concentrations, and that the latter can, therefore, only be used clinically to a limited extent. Since rizoenzymes are increasingly used in clinical practice, the present in vitro study investigated efficiency of enzymatic activity of rizoenzymes in comparison to pancreatin under various physiological and partly extreme environmental conditions. The lipolytic properties of two typical preparations containing digestive enzymes from porcine pancreatin and rizoenzymes were compared (same dosage of activity units) at different pH values (pH 3–9), with the addition of different bile salt concentrations (0–15 mmol/L sodium taurocholate). Lipolytic activity was measured by quantifying the fatty acids released from olive oil substrate by liquid chromatography–tandem mass spectrometry after enzymatic digestion. For both enzyme preparations, the lipolytic activity maximum was reached at pH 7 with comparable fatty acid conversion rates (57% pancreatin, 58% rizoenzymes). However, in contrast to pancreatin, rizoenzymes were already active for certain fatty acids from pH 3 to 4. At a bile salt concentration up to 10 mmol/L taurocholate, there was an increase in activity of both enzyme preparations (rizoenzymes 69% vs. pancreatin 58% enzymatic conversion). Only at rather unphysiological concentration of 15 mmol/L during EPI, there was a slight decrease in activity (to 56%) for the rizoenzymes. Rizoenzymes are an alternative therapeutic option for EPI. Relevant differences between rizoenzymes and pancreatin with regard to lipolytic activity under different physicochemical conditions could not be demonstrated in this study, whereas a potential advantage in favor of rizoenzymes activity at already low pH values was observed.