Biopolymers from fermentation

In research aimed at lower chemical costs for enhanced oil recovery, we are attempting a separation of this type, biopolymer from fermentation broth. The motivation is to eliminate the conventional precipitation of polymer by alcohol addition, a step which contributes a substantial fraction of production cost, perhaps as much as 40%, with the necessity to recover alcohol for recycle (Figure 1). Precipitation is necessary to prepare a dry product, economical to ship. (Concentrated broth, prepared at a central facility, is also proposed, at a penalty in transportation costs.)... 

Separation of biopolymer from fermentation broth. (Application mobility control for enhanced oil recovery.)... 

Biopolymer Extraction. Research interests involving new techniques for separation of biochemicals from fermentation broth and cell culture media have increased as biotechnology has grown. Most separation methods are limited to small-scale appHcations but recendy solvent extraction has been studied as a potential technique for continuous and large-scale production and the use of two-phase aqueous systems has received increasing attention (259). A range of enzymes have favorable partition properties in a system based on a PGE—dextran—salt solution (97) ... 

Xanthan gum [11138-66-2] is an anionic heteropolysaccharide produced by several species of bacteria in the genus Aanthomonas A. campestris NRRL B-1459 produces the biopolymer with the most desirable physical properties and is used for commercial production of xanthan gum (see Gums). This strain was identified in the 1950s as part of a program to develop microbial polysaccharides derived from fermentations utilizing com sugar (333,334). The primary... 

In February 2006, Japan s Mitsubishi Motors announced that it is to use the biopolymer, polybutylene succinate (PBS), in the interior of its new mini-car launched next year. In conjunction with Aichi Industrial Technology Institute, it has developed a material that uses PBS combined with bamboo fibre. PBS is composed of succinic acid, which is derived from fermented corn or cane sugar, and 1,4-butanediol. Bamboo grows quickly and is seen by Mitsubishi as a sustainable resource. In lifecycle tests, the PBS-bamboo fibre composite achieves a 50% cut in carbon dioxide emissions compared with polypropylene. Volatile organic compound levels are also drastically reduced, by roughly 85%, over processed wood hardboards. 

Salmiati Z, Ujang MR, SaUm MF, Md D, Ahmad MA (2007) IntraceUular biopolymer productions using mixed microbial cultures from fermented POME. Water Sci Technol 56 179-185 Schubert P, Steinbuchel A, Schlegel HG (1988) Cloning of the AlcaUgenes eutrophus poly-fL hydroxybutyrate synthetic pathway and synthesis of PHB in Escherichia coU J. Bacteriol. 170 5837-5647... 

Different routes for converting biomass into chemicals are possible. Fermentation of starches or sugars yields ethanol, which can be converted into ethylene. Other chemicals that can be produced from ethanol are acetaldehyde and butadiene. Other fermentation routes yield acetone/butanol (e.g., in South Africa). Submerged aerobic fermentation leads to citric acid, gluconic acid and special polysaccharides, giving access to new biopolymers such as polyester from poly-lactic acid, or polyester with a bio-based polyol and fossil acid, e.g., biopolymers . 

Consumer acceptance is not a big issue yet, but is one to keep an eye on. Supermarket chains in the UK have refused a biopolymer because it was derived from genetically modified plants, despite the fact that it is an eco-friendly material. There is even a discussion as to whether vitamins produced by fermentation... 

The melting temperature (Tm) of the biopolymer was determined from differential scanning calorimetry thermograms. The Tm value of the P (3HB) homopolymer was about 177°C and P (3HB) with 10% P(3HV) was about 150°C (Table l),but the Tm values of biopolymer extracted from E. coli HMS174 were about 166°C. The Tm of the sample was lower than that of the P (3HB) homopolymer, but higher than that of the P (3HB) with 10% P (3HV), because the P (3HV) content in the sample is only about 4.5% of the biopolymer produced. The PHV content in extracted biopolymer was low, the flexibility of extracted biopolymer was low, and different fermentation conditions should be investigated. 

The biopolymer extracted from the fermented broth was purified through successive washings with 70, 80, and 90% (v/v) ethanol P.A., respectively. The biopolymer was dried by introducing nitrogen gas under controlled heating. 

We estimate that biotechnology will be competing with approximately 30 percent of the total chemical market by 2010 on the basis of lower cost and/or superior product features. Approximately 10 to 20 percent of basic and intermediate chemicals could be affected by production through modern fermentation. Specialties will be replaced by enzymes and natural flavors, pigments and additives. Polymers will face competition from biopolymers that are competitive in price with both polyester and nylon. 

The butyrate or octanoate copolymer and butyrate or hexanoate or decanoate terpolymer have properties similar to those of higher-grade LLDPE (linear low-density polyethylene) and higher-grade PET (polyethylene terephthalate). They can be molded or converted into films, fibers, and nonwoven fabrics. The biopolymer is produced by low-cost fermentation or from wastestream substrates. 

The ionophores and several other specialty products are included in Table 13.8 for comparison purposes. Products of mammalian cell culture such as plasminogen activator and erythropoietin are included as fermentation products in this listing because they are normally manufactured by cellular processes in bioreactors. Aside from the five commodity chemicals in this table, the most dramatic change in the commercial chemicals produced by fermentation results from the impact of genetic engineering and recombinant DNA methods on the specialty products. Antibiotics and biopolymers (hormones, enzymes, etc.) with molecular structures too complex for conventional chemical synthesis will continue to be manufactured by microbial processes (Hinman, 1993). 

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