Growth-coupling

Previous studies have investigated batch fermentation of both carbon sources and microorganisms. The microorganisms will accumulate PHAs after the cell reached the maximum growth coupled with the depletion of nitrogen or phosphorus (Braunegg et al 1998 Wang Bakken, 1998 Chien et al, 2007). 

Edgar Two questions that we have talked about a lot are what causes cells to exit the cycle and stop proliferating, and how is cell growth coupled to the cell cycle control apparatus Does a coupling mechanism exist and does it vary in different developmental situations ... 

Edgar The competing model will be that fancy promoters are not used to control cell cycle genes, but instead there is some kind of growth coupling mechanism. 

The specific growth rate (ji) becomes of interest for the poly(3HB) content if the poly(3HB) synthesis is growth-coupled. The possible content is then independent of time and is determined by the relation of qp to p. [74] ... 

Reduction of Metals and Nonessential Elements by Anaerobes 225 Table 16.4. Growth coupled to reduction of metals and metalloids. 

While morphological evidence can be convincing and much can be learned from electron microscopy and molecular phylogeny, rigorous demonstration of bacterial Fe-oxidation requires isolation of organisms in Fe-enrichment cultures and observation of Fe accumulation or release from sulphides during in vitro growth coupled with C02 fixation (Juniper Tebo, 1995). Only then can the quantitative importance of microbial iron oxidation be determined. 

Caldtes associated with Mississippi Valley-type lead-zinc mineralization in Carboniferous limestone in Illinois show a marked decrease in 5 C during their growth coupled with only a small decrease in 5 0 (Figure 7.19). These changes indicate that early caldtes were very similar in composition to carbonates in the limestone, whilst late in the evolution of the hydrothermal system, fluids associated with the degradation of organic carbon become important (Richardson et al. 1988). 

Growth-coupled-to-orientation(SLC), also described as the open supramolecular liquid crystal,is an inter-... 

Fig. 2 Growth mechanisms. Schematic theoretical variation of DP (or length) with unimer concentration for linear supramolecular polymerization according to (a) multistage open association (b) helical growth (c) growth-coupled-to-orientation. C and C are eritieal eoneentrations coiresponding to (b) and (c). Occurrenee of liquid-eiystalline phases (N. H, L) is indicated. From Ref. [1]. Copyright 2002 Wiley-VCH.

Yeast was the first microbial host used by mankind for biotransformation of raw materials, and it marked the early developments of industrial biotechnology. Initially, Saccharomyces cerevisiae and closely related species were used because of their high fermentative capacity and based on the vast experience from alcoholic beverage production. While a high fermentation rate is favorable for the production of bioethanol and other primary metabolites, it implicates disadvantages for growth-coupled production. Consequently, a number of other yeasts have been developed for the production of biofuels, biochemicals, lipids, or recombinant proteins. 

Figure 3.1 Growth- and non-growth-coupled toy metabolic networlc (panels a and b, respectively) along with their associated phenotypic yield spaces (panels c and d, respectively). Both networks consist of nine irreversible reactions (diamond ffl -ff9), four internal metabolites (full rectangles), four external metabolites (checkered rectangles BM. biomass P, product of interest Q by-product 5, substrate note that the metabolite Q is the produa of two reactk>ns-A5 and A9) and five EFMs. In the phenotypic yield space EFMs are represented by full circles. Note that the point (1/0) in the phenotypic yield space of network B represents two EFMs with identical yields. The feasible yield space is bounded by the two axes and the dashed line. Growth-coupled production of P is achievable only in network A, but not in network B.

On the feasibility of growth-coupled product synthesis in microbial strains. Metab, Eng., 30, 166—178, doi 10.1016/j.ymben.2015.05.006. 

Burgard AP, Van Dien SJ, Burk Ml. (2009). Methods and organisms for the growth coupled production of 1,4-hutanediol. US Patent 20090047719A1. 

Figure 12.8 Schematic representation of (a) step-growth coupling of bivalent azide and bivalent acetylene telechelic polymers (b) polymer modi cation by CuAAC of pendant alkyne groups of polymers, e.g., poly(vinyl acetylene), with an azide-bearing substrate and (c) functionalization of polymer by CuAAC of pendant azide with alkyne-bearing functional moiety. Azide terminated dendrimers are similarly subjected to CuAAC with alkyne-derivatized functional moieties to achieve desired functionalization of dendritic macromolecules.

More recent considerations relating to the shape of the unimer and to the structure of SPs formed via the open SLC were presented by the author [89]. In particular, growth-coupled-to orientation needs not to be restricted to linear and discotic rigid assemblies. Helical SPs could also assemble by the open SLC mechanism. In fact, the stabilization of supramolecular helices (shown in Section n.B.2 to be due to a nucleation process) could be favored by the SLC even in the absence of nucleation. The process has some analogies with the selection of allowed ordered conformations occurring during crystallization. A related coupling between orientational and supramolecular order was discussed in... 

Verification of the open SLC model is based on a sudden increase of polymerization when the nematic phase appears (Figure 16). Data regarding the rigidity (persistence length) of the assembly are desirable. Systems for which growth-coupled-to-orientation was adequately documented are described below [85,150-152,156]. In the case of micelles (Table 3, polymer 14), Odijk [85] has critically... 

The foregoing discussion reveals the existence of seemingly different approaches to describe the assembly of different types of amphiphilic molecules. In particular, conventional surfactants and discotic molecules are described by the growth-coupled-to-orientation theory, while diblock copolymer molecules are described by the mean-field theory in terms of a balance between chain stretching and compatibility parameters. HopefiiUy, these differences ought to be rationalized in terms of a unified treatment. 

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