Production of inulinase: recovery and scale-up / Obtenção de inulinase: recuperação e ampliação de escala

AUTOR(ES)
DATA DE PUBLICAÇÃO

1995

RESUMO

It has been observed that the production of extracellular inulinase by Candida kefyr DSM 70106 was markedly affected by the rate of oxygen transfer to the medium. The highest inulinase activity (37,5 U.Ml-1) was attained at a KLa value (volumetric coefficient of oxygen transfer) equal to 43 h-1. As such, KLa was chosen as a criterion for scaling-up the bioreactor capacity from 15 L to 300 L. Once the fermentation ended, the whole fermented broth was frozen for further cell separation and inulinase purification. For that, three different processes were used, namely filtration (microfiltration, diafiltration and ultrafiltration), liquid-liquid extraction by reversed micelles and ion-exchange chromatography in fluidized bed. Microfiltration membranes differing in the chemical nature and on the pores diameter were used in cell separations. The highest filtrate flow (FF = 324 L.h-1.m-2) occurred when HVLP type membrane (0,45 µm pore diameter) was employed. Moreover, 99% of inulinase passed through the membrane. Several types of filtration modules were also studied. The rotatory filter, such as the "Biodruckfilter" (FF=300 L.h-1.m-2 and 99% of inulinase transmission), presented remarkable performance when compared with cassette and tubulartype filters, in which FF was lower than 50%. Furthermore, filtration carried out with a scaled-up cassette module presented a FF 45% lower than that observed on a smaller scale. Studies on liquid-liquid extraction by reverse micelles were made utilizing a cationic surfactant (BDBAC- [N-Benzyl-N-Dodecyl-N-bis(2-hydroxyethyl) ammonium chloride] and an anionic surfactant (AOT-sodium-di-2-ethyl-hexylsulphosuccinate). The use of BDBAC resulted in a recuperation of 91 % of the enzyme initially present, which decreased about 77% when the process was scaled-up. Neverthless, in both cases the increase in specific enzymatic activity was about 2.8 times. In comparison with the aforementioned processes, the ion-exchange chromatography in fluidized bed, in which inulinase purification and cell separation take place simultaneously, provided. an increase in specific enzymatic activity of about 4.3 times. After adsorption and elution of the chromatographic bed about 93% of the inulinase was recovered.

ASSUNTO(S)

chromatography enzimas enzymes cromatografia inulinase inulinase

ACESSO AO ARTIGO

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