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Title: BIOSYNTHESIS OF EMULSAN BIOPOLYMERS FROM AGRO-BASED FEEDSTOCKS

Author
item PANILAITIS, BRUCE - TUFTS UNIVERSITY
item CASTRO, GUILLERMO - TUFTS UNIVERSITY
item Solaiman, Daniel
item KAPLAN, DAVID - TUFTS UNIVERSITY

Submitted to: Journal of Applied Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/3/2006
Publication Date: 1/19/2007
Citation: Panilaitis, B., Castro, G., Solaiman, D., Kaplan, D.L. 2007. Biosynthesis of emulsan biopolymers from agro-based feedstocks. Journal of Applied Microbiology. 102:531-537.

Interpretive Summary: Emulsan is a biopolymer (large molecule) produced by bacteria. It is composed of a string of sugar molecules with fatty acids attached to them. Its physical and functional properties vary with the number and type of fatty acid attached to the molecule. Aside from having an emulsifying activity, emulsan also has biological function including macrophage (white blood cell) activation and adjuvant (immune response-enhancing) activity. There is a need to lower the cost of production and to improve the functional properties of emulsan. One approach is to develop the use of inexpensive and structurally diverse renewable feedstocks as starting materials (or substrates for its production. In this paper, we described our study to use the inexpensive agricultural feedstocks (i.e., soy molasses and tallow oil) to affect the chemical composition and/or biological activity of emulsan. The results showed that the two feedstocks tested can indeed support the biosynthesis of emulsan variants having different types of fatty acids attached. These variants exhibited comparable biological activity in comparison to the emulsan obtained using the more costly feedstocks. This work thus demonstrates the usefulness of agricultural coproducts as low-cost feedstocks for the production of the biologically active emulsan variants.

Technical Abstract: The need for biocompatible, biodegradable, and versatile biopolymers permeates many fields including environmental and food technology. The goal of the study presented here is to establish the utility of agricultural oils as an inexpensive carbon source to produce materials useful for biomedical materials and offer positive attributes in terms of green chemistry. Structural variants of the complex acylated polysaccharide, emulsan, secreted from Acinetobacter venetianus RAG-1, were biosynthesized in cultures supplemented with agricultural feedstocks to examine the feasibility of conversion of these substrates into value-added biopolymers. A. venetianus produced chemically and biologically distinct emulsan variants in culture on soy molasses and tallow oil. These variants possess significant biological function, including macrophage activation and adjuvant activity, in similar range to that observed for the standard emulsan formed on ethanol-fed A. venetianus. The results indicate that this novel family of biopolymers can be produced in significant quantities from the readily available renewable agricultural feedstocks and the resulting structures and functions can be correlated to the chemistry of these feedstocks. The significant quantities of agricultural oils produced annually represent an untapped source for bioconversion to valuable products. The results of this study confirm that the important polymer emulsan can be synthesized from this inexpensive carbon source.