196
Laboratory-scale conversion technology using corn starch and toluene complexant was developed in the late 1970s. The optimized parameters include 30 w% prehydrolyzed corn starch, 5 v% toluene, 50 °C conversion temperature, pH 6.8, and
5 days conversion time.
The scale-up of cyclodextrin conversion technology started in 1978 in the pilot
plant of Chinoin (plant IX). The cyclodextrin conversion (in presence of toluene
complexant) was implemented at 3 m
3
level. The preliminary pilot plant technology
manual describes a cyclodextrin glucosyltransferase-catalyzed corn starch conversion leading to a high beta-cyclodextrin-containing starch degradation mixture. The
downstream processing was based on a new development, namely, cyclodextrin
content was separated via its soluble ethanol complex form. With 30 v/v % ethanol
in the final conversion mixture, the beta-cyclodextrin and gamma-cyclodextrin are
soluble; other insoluble cyclodextrins and degraded starch reaction products can be
filtered off.
To realize this separation step, after filtration of final conversion mixture, the
filter cake containing toluene-cyclodextrin complex was re-suspended in water;
then the toluene content was eliminated by steam distillation. Beta-cyclodextrin was
separated from linear starch degradants and maltodextrins in soluble ethanol complex form. For this reason, purification technology involved a step of adding twofold ethanol to the concentrate. The resulting ethanol complex solution was hot
filtered, concentrated in vacuum, decolorized with charcoal, filtered, and crystallized. Using this technology 112 kg of pure beta-cyclodextrin was manufactured in
1978. The purity of resulting beta-cyclodextrin was >99.7%, and the overall yield
was 33%, calculated on corn starch reference. This procedure was applied for patenting in 1977, and that patent was granted in 1980 (Vakaliu et al. 1979), based on
a preliminary laboratory-scale production documentation compiled in 1977.
The high ethanol consumption, however, made the beta-cyclodextrin technology
too expensive. To reduce the producing costs, a new process was elaborated at
Chinoin Biotechnology Department. This concept was based on decaying the
remaining unreacted dextrins derived from the high molecular weight fraction of
conversion mixture. A thermostable alpha amylase of Bacillus amyloliquefaciens
(BAN 240 L enzyme) was applied at the end of the cyclodextrin glucosyltransferase
incubation period for this purpose. The resulting low viscosity conversion mixture
could be filtered without difficulties. The cyclodextrin-toluene complex-containing
filter cake was re-suspended in water, and toluene eliminated by steam distillation.
Then the diluted material was decolorized with active carbon and hot filtered. The
cyclodextrin-containing filtrate was concentrated in an evaporator thereafter. It was
decolorized again with active carbon, and finally beta-cyclodextrin was crystallized.
Based on initial laboratory-scale documentation, an industrial plant-scale technology was compiled by Biotechnology Department in 1979. Further experiments
started in 1981 for industrial scale-up in plant Chinoin-IV in 1982.
For elimination of remaining toluene, sugar, and maltooligosaccharide traces, an
additional purification procedure was inserted into the beta-cyclodextrin technology
in 1981. It was realized by the application of mixed styrene divinylbenzene polymerbased Varion KS and Varion AD ion exchangers. To satisfy ongoing press for the
É. Fenyvesi et al.
Laboratory-scale conversion technology using corn starch and toluene complexant was developed in the late 1970s. The optimized parameters include 30 w% prehydrolyzed corn starch, 5 v% toluene, 50 °C conversion temperature, pH 6.8, and
5 days conversion time.
The scale-up of cyclodextrin conversion technology started in 1978 in the pilot
plant of Chinoin (plant IX). The cyclodextrin conversion (in presence of toluene
complexant) was implemented at 3 m
3
level. The preliminary pilot plant technology
manual describes a cyclodextrin glucosyltransferase-catalyzed corn starch conversion leading to a high beta-cyclodextrin-containing starch degradation mixture. The
downstream processing was based on a new development, namely, cyclodextrin
content was separated via its soluble ethanol complex form. With 30 v/v % ethanol
in the final conversion mixture, the beta-cyclodextrin and gamma-cyclodextrin are
soluble; other insoluble cyclodextrins and degraded starch reaction products can be
filtered off.
To realize this separation step, after filtration of final conversion mixture, the
filter cake containing toluene-cyclodextrin complex was re-suspended in water;
then the toluene content was eliminated by steam distillation. Beta-cyclodextrin was
separated from linear starch degradants and maltodextrins in soluble ethanol complex form. For this reason, purification technology involved a step of adding twofold ethanol to the concentrate. The resulting ethanol complex solution was hot
filtered, concentrated in vacuum, decolorized with charcoal, filtered, and crystallized. Using this technology 112 kg of pure beta-cyclodextrin was manufactured in
1978. The purity of resulting beta-cyclodextrin was >99.7%, and the overall yield
was 33%, calculated on corn starch reference. This procedure was applied for patenting in 1977, and that patent was granted in 1980 (Vakaliu et al. 1979), based on
a preliminary laboratory-scale production documentation compiled in 1977.
The high ethanol consumption, however, made the beta-cyclodextrin technology
too expensive. To reduce the producing costs, a new process was elaborated at
Chinoin Biotechnology Department. This concept was based on decaying the
remaining unreacted dextrins derived from the high molecular weight fraction of
conversion mixture. A thermostable alpha amylase of Bacillus amyloliquefaciens
(BAN 240 L enzyme) was applied at the end of the cyclodextrin glucosyltransferase
incubation period for this purpose. The resulting low viscosity conversion mixture
could be filtered without difficulties. The cyclodextrin-toluene complex-containing
filter cake was re-suspended in water, and toluene eliminated by steam distillation.
Then the diluted material was decolorized with active carbon and hot filtered. The
cyclodextrin-containing filtrate was concentrated in an evaporator thereafter. It was
decolorized again with active carbon, and finally beta-cyclodextrin was crystallized.
Based on initial laboratory-scale documentation, an industrial plant-scale technology was compiled by Biotechnology Department in 1979. Further experiments
started in 1981 for industrial scale-up in plant Chinoin-IV in 1982.
For elimination of remaining toluene, sugar, and maltooligosaccharide traces, an
additional purification procedure was inserted into the beta-cyclodextrin technology
in 1981. It was realized by the application of mixed styrene divinylbenzene polymerbased Varion KS and Varion AD ion exchangers. To satisfy ongoing press for the
É. Fenyvesi et al.