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Adsorption of Streptococcus faecalis on diatomite carriers for use in biotransformations
Author(s) -
Anderson William A.,
Bay Pierre,
Legge Raymond L.,
Mooyoung Murray
Publication year - 1990
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.280470202
Subject(s) - adsorption , streptococcus , microbiology and biotechnology , chemistry , biology , bacteria , organic chemistry , genetics
Abstract Adsorption of cells on particulate carriers is potentially one of the most cost‐effective immobilization techniques available. Diatomite carriers, such as Celite, have desirable physical properties, are inexpensive, and are suitable for both mycelial and bacterial systems. This work investigated the use of diatomite carriers as a biocatalyst support in a packed‐bed reactor where L ‐tyrosine was enzymatically decarboxylated using adsorbed, non‐growing cells of Streptococcus faecalis . Composition of microbial adsorption on different Celite types, with mean pore sizes ranging from 0.55 to 22 μm, showed there was no significant difference in biomass loading capacity under the conditions used. Using Celite 560, biomass loadings in a packed‐bed reactor varied from 10 to 30 g dm −3 of reactor volume, which compares favourably with other adsorption methods. When used to decarboxylate L ‐tyrosine, the reactor was found to have a half‐life of 15–20 h. A combination of enzyme activity loss and slow leakage of biomass from the packed‐bed reactor was responsible for the decline in conversion. Treatment of the S. faecalis cells with glutaraldehyde significantly reduced the enzyme activity loss and extended the reactor half‐life to 65 h, but had little effect on the rate of cell leakage from the reactor. Further work on reduction of cell leakage rate seems necessary for evaluation of the system's practicality.