Growth and differentiation of plant cell cultures was increased when media were gelled with corn starch instead of agar. Dry weight of tobacco and wild carrot cell cultures on media gelled with starch was more than three times that of cultures on media gelled with agar. Higher yield of anthocyanin and dry weight of embryos were found in wild carrot cultures grown on media gelled with corn starch. The starch-mediated increase in growth and differentiation of wild carrot ceils was accompanied by an increase in density of the cultures shown by higher dry weight/fresh weight ratios.

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Corn syrups have been evaluated in media for embryogenesis, androgenesis and the production of secondary metabolites from plant tissue culture. In the systems examined, higher productivity was obtained with media containing corn syrups than with comparable media containing glucose or sucrose. Corn syrup did not increase growth of unorganized cell cultures. Increased productivity therefore reflects a syrup-mediated promotion of cell differentiation. The effects of corn syrup on increasing yields of secondary metabolites were evident only after several passages in syrup-containing medium. This shows the importance of monitoring production over several passages to determine the effect of different carbon sources on secondary metabolite production. Superiority of the syrup is due primarily to the component sugars maltose and glucose. Mixtures of these sugars gave higher yields of secondary products than either sugar used alone.Abbreviations: DP -degree of polymerization

A model is presented describing starch hydrolysis by Bacillus stearothermophilus α‐amylase at temperatures of 90 to 115°C and substrate concentrations of 24 to 36% solids. First order kinetics adequately describe both the enzyme decay and starch hydrolysis reactions. Quantitation of temperature, pH, added calcium and substrate concentration interactive effects on the first order rate constants is aided by applying standard statistical techniques of experimental design and data analysis. A method for determining residual α‐amylase activity in liquefact based on the Phadebas® dye release assay, and an osmometry method for determining degree of liquefact hydrolysis are described. Computer implementation of the model allows rapid graphical visualization as well as screening of ideas for improved starch hydrolysis processes.

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