Immobilization and morphology of Rhizopus sp. on Loofah Sponge

Fermentation is used as a mean to produce a variety of fermentation products. These products were in a high demand due to its uses as a raw material in many industries. Immobilization of Rhizopus sp. onto biomass support particles (BSP) as a whole-cells biocatalyst were studied to increase the production of these products from fermentation process. By using immobilization process, the complex procedures of isolation, purification and immobilization of extracellular enzyme can be avoided. Loofa sponge was selected as the biomass support particles to aid in immobilization of the cells. In this study, the growth of immobilized Rhizopus sp. on loofa sponge was compared in different cultivation medium and the presence of attachment of Rhizopus sp. onto loofa sponge was investigated using scanning electron microscopy (SEM). Next, the production of the metabolite was investigated from different media used. Rhizopus sp. was immobilized on loofa sponge in a various medium which were cassava dextrose, potato dextrose, hydrolyzed cassava, and soya dextrose. The process condition and other parameters which were temperature, pH, inoculum dilution, and weight of loofa sponge respectively fixed at 30oC, 7, 20 ml and 2 g. The highest growth for immobilized cells was in the cassava dextrose medium with 1.68 g/g followed by immobilized cells in potato dextrose broth with 1.30 g/g and lastly soya dextrose immobilized cells and cassava hydrolyzed cells with 1.25 g/g and 1.22 g/g respectively. The spores were proven to be found attached on the loofa sponge by the presence of mycelia that attached to the loofa sponge after immobilization process. Immobilized cells in the potato dextrose broth recorded the highest value with 7.66 g/L of lactic acid and 3.11 g/L of ethanol. The concentration of lactic acid, ethanol and glucose for immobilized cells were analyzed by High Performance Liquid Chromatography (HPLC).