1.3- Propanediol strains

In this chapter, we present part of our work on the conversion of bioglycerol into 1,3-propanediol, 2,3-butanediol and H2 using different microorganisms and discuss the use of a single bacterial strain isolated from anaerobic fermentation media, which is able to produce either diols or H2 according to the conditions in which it is grown. 

Strains Kl, K2 and K3 were used for the production of 1,3-propanediol under aerobic conditions. The conditions described in the Experimental section were used the starting concentration of glycerol was 30% by mass. Table 8.2 summarizes the results obtained. Strain K2 is the most active, showing a 47% conversion of glycerol after 144h and the best selectivity towards 1,3-propanediol. 

PD is the least toxic product in the glycerol fermentation, but nevertheless determines the achievable final concentration. A final concentration of propanediol around 60-70 g/1 is usually achieved with wild-type strains. More than 85 g/1 1,3-PD can be produced with these microorganisms in special fed-batch fermentations (unpublished results). With externally added 1,3-PD,... 

Cameron et al. [12] showed that recombinant E. coli can tolerate more than 100 g/1. The strain itself however produced little propanediol. In a recent study, Colin et al. [45] showed that C. butyricum can tolerate up to 83.7 g/1 propanediol when it is added externally. These values may represent the maximum achievable product concentration with wild-type strains. 

Experimental evidence of the involvement of a biradical intermediate in the decomposition of 3,3-dimethyl-l,2-dioxetane (10) has been obtained by radical trapping with 1,4-cyclohexadiene (CHD). Decomposition of 10 in neat CHD was shown to result in the formation of the expected 1,4-dioxy biradical trapping product, 2-methyl-1,2-propanediol (11) ° . However, more recently, it has been shown that the previously observed trapping product 11 was formed by induced decomposition of the dioxetane, initiated by the attack of the C—C double bond of the diene on the strained 0—0 bond of the cyclic peroxide (Scheme 9)"°. 

Papanikolaou, S., Muniglia, L., Chevalot, I., Aggelis, G. and Marc, I. 2002. Yarrowia Lipolytica as a Potential Producer of Citric Acid from Raw Glycerol. J. Appl. Microbiol., 92, 737-744. Papanikolaou, S., Ruiz-Sanchez, P., Pariset, B., Blanchard, F. and Fick, M. 2000. High Production of 1,3-Propanediol from Industrial Glycerol by a Newly Isolated Clostridium Butyricum Strain. J. Biotechnol., 77, 191-208. 

In contrast, selective hydrogenolysis of glycerol to 1,3-propanediol by means of chemo catalysis is still a challenging task. Although several attempts do exist with, for example, Pt/W03/Zr02 or Ir-ReOx/Si02 catalysts [48, 49], the enzyme-catalyzed route using bacterial strains is more efficient [42] and has been commercialized (see Table 2.2.1). 

Dioldehydratase was discovered in certain strains of Klebsiella pneumoniae [7,8]. It catalyses the irreversible conversion of vicinal glycols into the corresponding 2-deoxyaldehydes (Fig. 5). The best substrates are (R)- and (S)- 1,2-propanediol [9], although a number of other vicinal glycols are also accepted by the enzyme [10,11]. 

Antoniewicz MR, Kraynie DF, Laffend LA, Gonzalez-Lergier J, Kelleher JK, Stephanopou-los G. (2007). Metabolic flux analysis in a nonstationary system fed-batch fermentation of a high yielding strain of E. coli producing 1,3-propanediol. Metab Eng, 9, 277-292. 

Ashok S, Raj SM, Rathnasingh C, Park S. (2011). Development of recombinant Klebsiella pneumoniae Delta dhaT strain for the co-production of 3-hydroxypropionic acid and 1,3-propanediol from glycerol. Appl Microbiol Biotechnol, 90, 1253-1265. 

Homann T, Tag C, Biebl H, Deckwer WD, Schink B. (1990). Fermentation of glycerol to 1,3-propanediol by Klebsiella and Citrobacter strains. Appl Microbiol Biotechnol, 33, 121-126. 

Huang YN, Li ZM, Shimizu K, Ye Q. (2012). Simultaneous production of 3-hydroxypropionic acid and 1,3-propanediol from glycerol by a recombinant strain of Klebsiella pneumoniae. Bioresource Technol, 103, 351-359. 

Ma Z, Shentu XP, Bian YY, Yu X. (2012). Effects of NADH availability on the Klebsiella pneumoniae strain with 1,3-propanediol operon over-expression. J Basic Microbiol. doi 10.1002/jobm.201100580... 

Oh BR, Seo JW, Heo S Y, Hong WK, Luo LH, Son JH, Park DH, Kim CH. (2012). Fermentation strategies for 1,3-propanediol production from glycerol using a genetically engineered Klebsiella pneumoniae strain to eliminate by-product formation. Bioproc Biosyst Eng, 35, 159-165. 

Papanikolaou S, Ruiz-Sanchez P, Pariset B, Blanchard F, Pick M. (2000). High production of 1,3-propanediol from industrial glycerol by a newly isolated Clostridium butyricum strain. J Biotechnol, 11,191-208. 

Petitdemange E, Diirr C, Abbad-Andaloussi S, Raval G. (1995). Fermentation of raw glycerol to 1,3-propanediol by new strains of Clostridium butyricum. Ind Microbiol Biotechnol, 15, 498-502. 

PD is currently produced commercially in small quantities by chemical synthesis using the toxic feedstock acrolein. Although 1,3-PD has not been produced on a large scale, there are dozens of potential uses in polymer synthesis and as a chemical intermediate (26), Cameron has also been involved in studies on strains of Clostridium thermosaccharolyticum that produce R(-)-1,2-propanediol, a useful chiral building block in organic synthesis (27),... 

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