Cultivation of Fungal Mushrooms for Production of Citric and Oxalic Acids

Abstract

The aim of this study is to explore the possibility of edible fungi to produce citric acid and / or oxalic acid in submerged culture, for use in food and pharmaceutical industries. Of 9 strains tested, only 4 were able to produce citric and oxalic acids; 3 belongs to Pleurotus species ( ostreatus, sajor-caju and colombimus ) and one belong to Lentinus edodes. Two strains, Pleurotus ostreatus and Pleurotus sajor-caju, were found to possess considerable possibilities. Therefore, a comprehensive study of the cultural requirements for maximum citric and biomass production with respect to different N and C sources, trace elements, biofactors, pH, buffers, inoculum size, incubation temperature and period, and agitation speed, was undertaken. Utilization of sugar-cane molasses for production of citric acid and evaluation 9 of mycelium biomass, as a microbial protein source were also elucidated. <t The most suitable medium was found to be one containing ( g/1 ): ; sugar-cane molasses ( ferrocyanide-treated ) ,100 ; yeast extract ; 4.3 CaC0,, 5.5 ; Fe$SO,- 7H,0, 0.003 ; ZnSO,-7H,0, 0.0045; MASO,-1H,0, % 0.003 ;MgSO,-7H,0, 0.75; KHPO,, 1.0; CaCL,-3H,0,0.35 ; Na,Mo0,, 0.003 ; vitamin mixture(9 vitamins,each 50-100 u g/l); pH 5.5. An inoculum