Fumaric acid production by Rhizopus oryzae and its facilitated extraction via organic liquid membrane

摘要

Microbial fermentations are efficient alternatives to different manufacturing practices being followed for industrially important compounds like organic acids, food and pharmaceutically active products. However, the attractions offered by microbial processes are overshadowed by the costs associated with downstream processing involved in the recovery of pure products from such systems. Reduction of the cost in terms of financial and energy related inputs have been the goal of recent ongoing research in the field of bio-processing. This study has been focused towards development of an efficient method for simultaneous extraction of products from microbial fermentation. Through the study, the domain of liquid membranes and the possibilities of energy efficient extraction of microbial products from ongoing processes have been investigated. Liquid membrane system involves a liquid which is immiscible with the source and receiving solutions serves as a semi permeable barrier between these two liquid phases. The study uses a fumaric acid produced through fermentation of Rhizopus oryzae on Potato Dextrose Broth (PDB) under aerobic conditions as a model sample for extraction analysis. The culture media, that is presumably rich in fumaric acid and some other acidic products, has been subjected to extraction through liquid membrane based process. The reduction in concentration of sample used as source is measured titrimetrically. Thin layered chromatography has been deployed at certain instances for qualitative verification of the concentrations. The set up consisted of a modified layered 'liquid membrane’ setup for a ‘fumaric acid’ source, with toluene as organic membrane and sodium hydroxide as strip phase. The liquid membrane contained a carrier for assisted transfer and was agitated. Maximum extraction takes place during the first 20 to 30 min of the run as fumaric acid concentration falls to almost 40% of its initial concentration.