Biomass production, carbon and oxygen consumption by Rhizopus arrhizus grown in submerged cultures on thin liquid films or immobilized on fibrous and particulate materials

Abstract

Oxygen consumption of Rhizopus arrhizus cultures was studied in order to understand why anaerobic-type metabolism takes place during growth, with high lactic acid synthesis. Rather than insufficient oxygen supply, pellet-type morphology was found to be responsible. Cultures with carriers and on thin liquid films were investigated with very good results for the second method. Not only was biomass production improved, but also carbon consumption was higher and lactic acid synthesis less compared with traditional submerged flask cultures.

Recent Advances on Filamentous Fungal Biofilms for Industrial Uses

“…Representatives of Zygomycetes and Ascomycetes have also been used in passively immobilized (biofilm) systems for several purposes. Among the Zygomycetes, some species of Rhizopus were used as biofilms developed on pumice particles, porous cellulose, and polyurethane foam for the production of lactic acid, dextran, or lipase [145][146][147][148][149][150], Mortierella isabellina biofilms on polyurethane foam were used for the production of dehydroabietic, abietic, and isopimaric acids [151], and Thermomucor indicae-seudaticae biofilms on loofa sponge were used for the production of thermostable glucoamylase [152]. Finally, among the Ascomyteces, Penicillium chrysogenum biofilms developed on polycarbonate or polyurethane foam were tested for the production of penicillin [153,154], Penicillium frequentans was found to form biofilms during the deterioration of granite-made monuments [155], biofilms of Fusarium moniliforme on loofa sponge were used in repeated batch operations for the production of gibberellic acid from milk permeate [156], acid phosphatase was produced by biofilms of Humicola lutea developed on polyurethane foam [157], Neurospora crassa biofilms on capillary membranes were used for the bioremediation of phenols [158], and Trichoderma reesei biofilms on nylon-webs, stainless steel particles or polyester cloth were used for cellulase production [44,[159][160][161].…”