Inexpensive carbon sources

Ability to utilize several inexpensive carbon sources... 

No doubt the cost of xylanolytic enzymes will be one of the factors determining their application in the pulp and paper industry as well as in other areas. Economically feasible xylanase production can be achieved in paper mills employing xylanase-positive transformants of common industrially used microorganisms that are capable of utilizing inexpensive carbon sources originating there. A substantial improvement in the production of xylanolytic systems can be expeaed from mutants of non-cellulolytic microorganisms that are resistant to catabolic repression. Such mutants usually exhibit hyperproduction of extracellular enzymes. 

It has been accounted that, on a production scale of PHB of 100,000 tons per year, the production costs will decrease from US 4.91 to US 3.72 kg , if hydrolysed com starch (US 0.22 kg ) is chosen as the carbon source instead of glucose (US 0.5 kg ) [33]. But this is still far beyond the cost for conventional polymers, which in 1995 was less than US 1 [32]. Lee et al. estimated that PHB and mcI-PHA can be produced at a cost of approximately US 2 kg [36]. The precondition therefore would be attaining high productivity and the use of inexpensive carbon sources. Among such substrates, molasses [37], starch [38], whey from the dairy industry [37-42], surplus glycerol from biodiesel production [39, 43], xylose [44, 45], and plant oils [46] are available. 

Zamzow, K.L. T.K. Tsukamoto G.C. Miller. Waste from biodiesel manufacturing as an inexpensive carbon source for bioreactors treating acid mine drainage. Mine Water Environ. 2006, 25, 163-170. 

Haloarcula, have been reported to have the ability to synthesise PHA from inexpensive carbon sources and PHA from these strains could be extracted easily compared with that of bacteria. Strain IKYSl, which exhibited the highest similarity with Natrinema pallidum JCM 8980 (99%), was isolated from a Tuzkoy salt mine, Tuz lake and its saltern of Kayacik, using cheap substrates such as corn starch, sucrose, whey, apple, melon and tomato wastes [39]. 

For the bacterial production of PHAs by recombinant strains, recombinant E. coli has been commonly used for PHA production thanks to its convenience for genetic manipulation, fast growth, high final-cell density, and ability to utilize inexpensive carbon sources. Metabolix and Jiang Su Nan Xian Co. Ltd employed recombinant E. coli for their PHA production. 

Tsuge T. Metabolic improvements and use of inexpensive carbon sources in microbial production of... 

For instance, Ralstonia eutropha is well established as one of the best known bacteria among PHAscr producing microorganisms and has several advantages for efficient PHA production as a recombinant host strain. R eutropha can intrinsically synthesize PHAs from various renewable inexpensive carbon sources, sugars and plant oils. However R. eutropha produces only PHAscl-... 

Second, it is an inexpensive carbon source, which can be incorporated into a variety of organic compounds in its entirety without producing any undesirable by-products. Since its toxicity problem can satisfactorily be dealt with in most instances, CO is, in fact, an environmentally friendly and convenient C source in an overall sense, even though extensively engineered apparati, which must often be operated at high pressures and temperatures, are required in many instances. 

Despite the many advantages of biodegradable plastics, the commercialization of PHAs still has limited success. One of the reasons is the cost of the substrate for the PHA production via fermentation. Hence, the choice of a suitable, renewable, and inexpensive carbon source is a critical factor that determines the economic feasibility of a PHA producing process. 

Carbon monoxide is a valuable and inexpensive carbon source, is thermally stable and chemically... 

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