One-step fermentation

There are a total of three ascorbic acid processes either in place or in late stages of development with firm expectations of commercialization (i) the traditional chemical Reichstein-Griissner synthesis (ii) the two-step fermentation process to 2-ketogulonic acid with subsequent chemical esterification/lactonization to ascorbic acid and (iii) the one-step fermentation to 2-ketogulonic acid with the same last chemical step. Figure 20.8 and Table 20.3 provide an overview of the three processes. 

One-Step Fermentation to 2-Ketogulonic Acid with Chemical Step to Ascorbic Acid... 

BASF s vitamin B2 process (a one-step fermentation process as opposed to an eight-step chemical synthesis) is another example of sustainable processes by bioroutes it reduces of 40% the environmental impacts and the costs. Novozymes ... 

Some bacteria such as Lactobacillus sp. produce protease as well as organic acid on bio-fermentation. These strains are ideal for simple one-step fermentation to extract chitin from the biomaterials. By a microorganism, DM and DP occur concomitantly in a batch culture. For shrimp heads, 83% DP and of 88% DM and for shrimp shells of 66% DP and 63% DM were achieved with L. plantarum 541 (Rao and Stevens 2005). The fermentation of shrimp biowaste has been optimized at pH 6.0 using 10% L. plantarum inoculum and 5% glucose, and pH 6.0 adjusted with acetic acid, which resulted in simultaneous 86% DM and 75% DP of the sohd fraction (Rao et al. 2000). Moreover, DP of 97.9% and DM of 72.5% were achieved at 72h after fermentation of shrimp (Penaeus monodori) biowaste using Pediococcus acidolactici CFR2182 (Bhaskar et al. 2007). 

Gao J, Xu H, Li QJ, Feng XH, Li S. (2010). Optimization of medium for one-step fermentation of inulin extract from Jerusalem artichoke tubers using Paenibacillus polymyxa ZJ-9 to produce R,R-2,3-butanediol. Bioresour Technol, 101, 7087—7093. 

Abstract Vitamin C, an important organic add, is widely used in the industries of pharmaceuticals, cosmetics, food, beverage and feed additives. Compared with the Reichstein method, biotechnological production of vitamin C is an attractive approach due to the low cost and high product quality. In this chapter, biosynthesis of vitamin C, including one-step fermentation processes and two-step fermentation processes are discussed and compared. Furthermore, the prospects of the biotechnological production of vitamin C are also presented. 

Keywords Vitamin C 2-keto-L-guIonic acid Fermentative production One-step fermentation... 

According to the production process, vitamin C production by biotechnology can now be divided into two-step fermentation and one-step fermentation. The two-step fermentation including tandem fermentation process that uses glucose as substrate and the fermentation process that uses D-sorbitol as substrate (Fig. 12.2). For the... 

Therefore, if the vitamin C or its direct precursor, 2-KLG, could be produced by one single step fermentation process, the final cost of the vitamin C will be significantly decreased. Current research on the one-step fermentation process is focnsed mainly on the following three aspects (1) Classical two-step based one-step fermentation process for 2-KLG production (2) Innovative two-step based one-step fermentation process 2-KLG (3) Direct production of vitamin C from glucose. 

Classical Two-Step Based One-Step Fermentation Process... 

Fig. 12.3 Classical two-step based one-step fermentation process ( Recombinant strains with different dehydrogenase). The D-glucose was hydrogenated to form D-sorbitol. The D-sorbitol was directly converted into 2-KLG with a G. oxydans strain or a E. coli strain (or any other potential strains) with the three different kinds of dehydrogenases. The 2-KLG was then esterified and lactonized to form vitamin C...

However, after the report of the innovative two-step fermentation process, the research on the classical two-step based one-step fermentation process seems to be suspended. Few literatures about metabolic engineering of G. oxydans for one-step vitamin C production could be found after then. 

Cadaverine (diaminopentane, DAP), a carbon-5 aliphatic metabolite, is a minor member of the biogenic polyamine family. It owes its trivial name to its first discovery in 1885 during systematic investigation of the putrefaction process of human cadavers [52]. In contrast to DAB, there is no efficient petrochemical production route available, which for a long time hampered its industrial application in the polymer industry. However, several bio-based production processes have meanwhile been developed for DAP production from renewable resources [6, 12, 15-17, 53]. Only recently, Cathay introduced the fully biobased polyamide PA5.10 Terryl , which entered the market in 2015. While the proprietary production process relies on biocatalytic conversion of the rather high-priced fine-chemical lysine, other attempts aim at a fully novo biosynthesis with streamlined cell factories for the direct fermentative production of DAP from cheap conventional fermentation feedstock. For establishing a one-step fermentation process for DAP, the industrial lysine producers E. coli and C. glutamicum were therefore the ideal metabolic chassis. 

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