Recovery and purification of Aspergillus niger phytase from crude extract using AOT / isooctane reversed micelles.

This work describes the successful extraction of Aspergillus niger phytase from a crude extract (CE) obtained from solid-state fermentation by reversed micelle system using anionic surfactant sodium bis (2-ethylhexyl) sulfosuccinate (AOT) in isooctane achieved in two simple steps: forward and backward extractions. The effects of potassium chloride (KCl) concentration, pH of the aqueous solution, and AOT concentration that affect the system were examined. The best result for the forward extraction was obtained with the CE solution at pH 4.0, 50 mM KCl, and 100 mM AOT, while for the backward extraction the best result was achieved with a stripping aqueous solution at pH 5.5 containing 200 mM KCl, achieving a purification factor of 4.03, 1.15 times higher than that reported for the conventional purification process. Phytase purity was demonstrated by SDS-PAGE (89 kDa) and its activity by zymogram, confirming the efficiency of the process with low time consumption (∼40 min).

Improvement of L(+)-lactic acid production from cassava wastewater by Lactobacillus rhamnosus B 103.

BACKGROUND: L(+)-Lactic acid is used in the pharmaceutical, textile and food industries as well as in the synthesis of biodegradable plastics. The aim of this study was to investigate the effects of different medium components added in cassava wastewater for the production of L(+)-lactic acid by Lactobacillus rhamnosus B 103. RESULTS: The use of cassava wastewater (50 g L(-1) of reducing sugar) with Tween 80 and corn steep liquor, at concentrations (v/v) of 1.27 mL L(-1) and 65.4 mL L(-1) respectively led to a lactic acid concentration of 41.65 g L(-1) after 48 h of fermentation. The maximum lactic acid concentration produced in the reactor after 36 h of fermentation was 39.00 g L(-1) using the same medium, but the pH was controlled by addition of 10 mol L(-1) NaOH. CONCLUSION: The use of cassava wastewater for cultivation of L. rhamnosus is feasible, with a considerable production of lactic acid. Furthermore, it is an innovative proposal, as no references were found in the scientific literature on the use of this substrate for lactic acid production.