PRODUCTION OF 1,3-PROPANEDIOL USING Klebsiella oxytoca NRTL B-199
Integration of life sciences & engineering
Integration of Life Sciences & Engineering - Poster (T5-P)
Keywords: 1,3-propanediol, fermentation, taguchi
The recent development of a new polyester called poly(propylenterephtalate), with unique properties for the fiber industry has increased the attention towards the production of 1,3-propanediol (1,3-PD), which has this and other applications in cosmetics, foods, lubricants and medicines.
This compound, 1,3-PD, can be produced by two methods: chemical and biotechnological synthesis. The latter is more attractive because it is carried out using milder operational conditions than the first one and it does not generate toxic by-products. Moreover, the microbial process can use glycerol as substrate, therefore, it will be a very suitable compound when it abounds in the market due to the increase of biodiesel production in which it is the main by-product. Glycerol can be naturally fermented into 1,3-PD by bacteria belonging to the genera Klebsiella, Clostridia, Citrobacter and Enterobacter under anaerobic or microaerobic conditions [1]. In the biological production of 1,3-PD, a series of by-products (such as acetic acid, ethanol, 2,3-butanediol, etc.) decrease the yield in 1,3-PD.The highest yields are reported when bacteria of genera Klebsiella are employed [2]. The microorganism used in this study has been Klebsiella oxytoca NRTL B-199.
The aim of this work is to identify the optimal medium composition which maximize both the growth of K. oxytoca and the production of 1,3-PD. The Taguchi method was applied to determine and optimize the nutrients requirements, taking into account both responses biomass growth and glycerol utilization into 1,3-PD production. This method facilitates identifying the influence of individual factors by establishing the relationship between variables and operational conditions and finally to establish the performance at the optimum levels obtained with a few experiments predicted by the use of the orthogonal array designs [3].
The experimental program was designed for four factors (glycerol, phosphate and MgCl concentrations; and the K:Na ratio) at three levels with orthogonal array layout of L9 (nine experimental trials). Experiments were carried out growing K. oxytoca at 30 ºC, in an orbital shaker at 250 r.p.m. during 24h. Cell growth was monitored as Optical Density at 600 nm. The concentration of glycerol, 1,3-PD, and the other by-products were determined by HPLC using an Aminex HPX-87H column and a refractive index detector.
The results obtained after the application of the Taguchi method to the experimental data show a clear influence of the chosen factors on both the biomass growth and the 1,3-PD production. Therefore, an optimal medium composition was determined.
References:
[1] Chen, X.; Xiu, Z; Wang, J.; Zhang, D; Xu, P., Enz. Microb. Technol. 33, 386-394 (2003).
[2] Huang, H.; Gong, S.Cheng; Tsao, G.T. Appl. Biochem. Biotechnol. 98-100, 687-691 (2002).
[3] Taguchi, G. “Introduction to Quality Engineering ”, Ed. Asian Prod. Org., Tokyo, Japan (1986).
Presented Wednesday 19, 13:30 to 15:00, in session Integration of Life Sciences & Engineering - Poster (T5-P).
