Magnetik nanotanecik içeren alginata tutuklanmış mikroorganizma ile laktik asit üretimi
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Date
2021
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Fen Bilimleri Enstitüsü
Abstract
The aim of the study is to immobilized Lactobacillus casei (DSM20011) microorganism, to produce lactic acid from glucose, optimize fermentation conditions with Response Surface Method (RSM) and to find kinetic rate constants. Fe3O4 nanoparticles were used in the immobilized. Fe3O4 nanoparticles were synthesized by co-precipitation method, and the synthesized Fe3O4 nanoparticles were functionalized separately with APTES and Dopamine. Cell immobilized experiments were performed separately with functionalized Fe3O4 nanoparticles and alginate- Fe3O4 nanoparticles, and lactic acid production from immobilized Lactobacillus casei cells was studied. Since the desired amount of immobilized of the nanoparticles could not occur, the microorganism was immobilized in the calcium alginate containing nanostructure of Fe3O4 and the production parameters on lactic acid production were examined. In the preliminary studies investigated the effects of pH and temperature, 14.3 g/L lactic acid was obtained at 6.5 pH and 25 ° C temperatures. The effects of microorganism concentration, substrate concentration and test duration parameters on lactic acid concentration were investigated in RSM experiments. The highest results in lactic acid concentration have been reached in the studies in which the microorganism concentration was 4.5 g/L, the substrate concentration was 30 g/L and the test period lasted 96 hours. As a result of these values, the lactic acid concentration reached 28.1 g/L. In these conditions, reuse of immobilized microorganisms were examined and 72.8% of the lactic acid concentration was preserved at the end of the fourth use. In the second part of the study, lactic acid production kinetics with immobilized microorganisms were examined, and it was determined that the kinetics fit the substrate activation model. Kinetic constants, respectively; rsmax = 11.385 mmol/L.h, K1 = 31.9012 mmol/L and K2 = 0.7285 mmol/L. In the study, the efficiency coefficient was found to be approximately 1.00 and it was determined that there were no observation the intra and interparticle resistances. Thus, the constants in the found rate equation are considered as real rate constants in the unresistance state.
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Lactobacillus casei, Mikroorganizma, Cevap yüzey yöntemi, RSM, dsm20011, Fe304