A New Kinetic Model for the Accumulation of Poly-3-hydroxybutyrate in Alcaligenes eutrophus

Abstract

A new kinetic model is proposed for the accumulation of poly(3-hydroxybutyrate) (PHB) in Alcaligenes eutrophus. The model developed is closely related to the descriptive model of Harkins for the emulsion polymerization process. The PHB accumulation is discussed in terms of polymerization events such as initiation, propagation and termination, taking into account the heterogeneous nature of the system. Experimental results on the PHB accumulation in Alcaligenes eutrophus can be described in both a quantitative and qualitative manner by the model. Further, it is shown that the decrease in the rate of polymerization during the PHB accumulation can be explained by coalescence of the granules. The decrease of the molecular weight of the polymer formed during the accumulation process can be fully explained in terms of the kinetic mechanisms of progapation and chain transfer, and the effect of granule size on these. 0 1995, Huthig &

Kinetic modeling of poly(β-hydroxybutyrate) production and consumption byParacoccus pantotrophus under dynamic substrate supply

“…This is incorporated in our simplified black box approach by the correlation between f max PHB and . PHB accumulation has been modeled as a two-stage process (Kurja et al, 1994), a granule formation stage followed by a granule growth stage. The rate of polymerization of HB-monomer to PHB is constant during this second stage because both the monomer concentration and the number of granules are constant.…”

“…It can be assumed that during the PHB production experiment only granule growth will be of importance. The maximum specific PHB production rate q P max as used in this article could then be related to the maximum HB-monomer polymerization rate as described by Kurja et al 1994).…”

Biosynthesis of poly-(R)-3-hydroxyalkanoate: An emulsion polymerization

“…Toward these aims, studies are currently under way utilizing kinetic experiments typical for emulsion polymerization to study bacterial polymerization. Preliminary results indicate that the analogy indeed explains many of the unknown features of granule formation [28].…”

Aspectos cinéticos de polimerización y copolimerización en emulsión

“…El nombre "polimerización en emulsión" se ha utilizado para describir la polimerización por radicales libres de monómeros muy poco solubles en agua, por la cual se forman partículas de látex sintéticas. Polimerización en emulsión no convencional puede definirse entonces (Kurja et al, 1997) como aquellos procesos donde el producto es un látex polimérico que fisicamente se parece a un látex de polimerización en emulsión y que no puede ser clasificado en otra forma reconocida de polimerización heterogénea (por ejemplo. suspensión, dispersión).…”

“…suspensión, dispersión). Algunos métodos no convencionales de polimerización en emulsión son los siguientes (Kurja et al, 1997). Reacciones del tipo de la homólisis y la heterólisis son la primera etapa (iniciación) de jas polimerizaciones por radicales libres e iónica, respectivamente.…”