2008 Annual Report
1a.Objectives (from AD-416)
The overall objective is to develop fermentation-based bioprocess systems that utilize the renewable agricultural fats, oils and coproducts (AFOC) as feedstocks to ultimately produce value-added bioproducts with enhanced properties and environmental benefits. Specific objectives are to expand the list of bioproducts producible via the fermentation of AFOC, to increase yields, expand variety, and improve properties of the target bioproducts via strain improvement, fermentation manipulation, and post-production modification; and to develop end-product applications for the bioproducts.
1b.Approach (from AD-416)
The capability of various AFOC to support cell growth of microorganisms that produce the target bioproducts -- rhamnolipids (RL), sophorolipids (SL), poly(hydroxyalkanoates) (PHA), gamma-polyglutamic acid and cyanophycin -- will be investigated. Genes needed for efficient production of bioproducts from AFOC will be identified, cloned, characterized and expressed. Chimeric genes and mutants having novel substrate specificity will be generated from PHA synthase genes with different PHA compositional profiles. Genes of enzymes or regulatory proteins involved in the biosynthesis of SL in Candida and RL in Pseudomonas will be cloned and characterized for subsequent protein and metabolic engineering to improve product variety and yield. Fed-batch and continuous culture techniques will be explored to increase the yields of bioproducts from fermentation of AFOC. Sophorolipids will be used to prepare new materials such as gemini surfactants, polymers of SL, value-added fatty acids, and bolaamphiphiles. Reactive functional groups, especially amino groups, will be incorporated to the sidechains of PHA for altered property and subsequent derivatization.
Project researchers had variously verified the first successful biosynthesis of medium-chain-length polyhydroxyalkanoates (mcl-PHA) containing methyl group(s) along the side-chains of the biopolymer; achieved an increased production yields (to greater than 1 g/L) of polyhydroxybutanoate from glycerol feedstock by increasing inoculum size and varying the total fermentation times; synthesized, characterized and supplied sophorolipids (SL) to collaborating scientists for applications in hide preservation and in nanoparticle applications; initiated studies that alter the sophorolipid biosurfactant’s architecture by swapping out the hydrophobic (water-averse) part of the molecule with a less hydrophobic moiety, with the goal of making the SL more water soluble; synthesized a glycerol-derived building block that also contains an amine and a carboxylic acid for use in preparing hyperbranched polymers; identified a Pseudomonas syringae promoter capable of expressing a green-fluorescence-protein reporter gene in several mcl-PHA-producing pseudomonads; carried out fermentation studies with yeast transformants containing a putative SL-biosynthesis gene; performed electrotransformation studies to develop methods for introducing foreign gene into Candida bombicola; designed and constructed new recombinant plasmids to achieve expression of alpha-galactosidase genes in microbes for soy molasses utilization. NP 306, Quality and Utilization of Agricultural Products; Component 2. New Processes, New Uses, and Value-Added Foods and Biobased Products; Problem Area 2b. New Uses for Agricultural By-products.
New highly versatile functionalized membrane components: There is a need for new structural variants of fats and oils (generically known as lipids) for novel uses as components in biosensors and as templates for micro-patterned inorganic materials such as selective adsorbents. Scientists at Eastern Regional Research Center, Wyndmoor, PA, have developed technology to prepare lipids that can be selectively modified with a wide variety of “molecular cargo.” These novel lipids possess chemically reactive groups which can link to each other or to the “molecular cargo.” With this methodology, the scientists have appended a sugar group and a protein component to a lipid. The expected impact is the creation of new membrane films/surface and sensors through the delivery of these “cargo molecules” to a specific side of a membrane or the surface of a sensor. Dimeric lipids where two of the novel lipids are linked have also been prepared for potential use as improved types of surfactants and detergents. (NP#306, Quality and Utilization of Agricultural Products; Component 2. New Processes, New Uses, and Value-Added Foods and Biobased Products; Problem Area 2b. New Uses for Agricultural By-products.)
5.Significant Activities that Support Special Target Populations
|Number of Active CRADAs||2|
|Number of the New MTAs (providing only)||1|
|Number of Non-Peer Reviewed Presentations and Proceedings||7|
Ashby, R.D., Solaiman, D., Foglia, T. 2008. Property control of sophorolipids: influence of fatty acid substrate and blending. Biotechnology Letters. 30:1093-1100.
Zerkowski, J.A., Nunez, A., Solaiman, D. 2008. Structured Estolides: Control of Length and Sequence. Journal of the American Oil Chemists' Society. 83:277-284.
Solaiman, D., Ashby, R.D., Catara, V., Licciardello, G. 2008. Genetic organization of pha gene locus affects phaC expression poly(hydroxyalkanoate) composition and granule morphology in Pseudomonas corrugata. Journal of Industrial Microbiology and Biotechnology. 35:111-120.