Growth rate dependence of enzyme synthesis in chemostat cultures: α‐amylase, β‐galactosidase, acid phosphatase and β‐fructosidase

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Abstract
Specific rate of enzyme synthesis in microbial cells was correlated to specific growth rate in chemostat culture using three strains of microorganism. α‐Amylase production by Bacillus subtilis was linearly associated with growth rate in a glucose‐limited chemostat culture. β‐Galactosidase production by Saccharomyces fragilis was rather invariable with growth rate in a galactose medium. β‐Fructosidase production by Saccharomyces carlsbergensis in a phosphate‐poor glucose medium was independent on growth rate, except at low dilution rates where it increased with growth rate. Production of acid phosphatase by the same microbe showed a maximum at a particular intermediate dilution rate. These relationships were summarised with an equation of induction—repression model. Comparison of the chemostat results with those of batch fermentation provided some enhancement factors of a continuous fermentation: 1.23–9.82 regarding enzyme productivity and 0.53–2.88 regarding enzyme concentration. The production of β‐fructosidase was much improved among the enzymes tested when continuous culture methods were used.