251 results about "PHA biosynthesis" patented technology

Devices formed of or including biocompatible polyhydroxyalkanoates are provided with controlled degradation rates, preferably less than one year under physiological conditions. Preferred devices include sutures, suture fasteners, meniscus repair devices, rivets, tacks, staples, screws (including interference screws), bone plates and bone plating systems, surgical mesh, repair patches, slings, cardiovascular patches, orthopedic pins (including bone filling augmentation material), adhesion barriers, stents, guided tissue repair / regeneration devices, articular cartilage repair devices, nerve guides, tendon repair devices, atrial septal defect repair devices, pericardial patches, bulking and filling agents, vein valves, bone marrow scaffolds, meniscus regeneration devices, ligament and tendon grafts, ocular cell implants, spinal fusion cages, skin substitutes, dural substitutes, bone graft substitutes, bone dowels, wound dressings, and hemostats. The polyhydroxyalkanoates can contain additives, be formed of mixtures of monomers or include pendant groups or modifications in their backbones, or can be chemically modified, all to alter the degradation rates. The polyhydroxyalkanoate compositions also provide favorable mechanical properties, biocompatibility, and degradation times within desirable time frames under physiological conditions.

A system and method for converting organic wastes to biodegradable thermoplastic materials including polyhydroxyalkanoates is disclosed, which method includes treating the organic wastes with an acidogenic microbial population to form fermentative organic acids, and polymerization of the organic acids by PHA-producing microbial species to form PHAs. The system includes a first compartment for acidogenesis of organic wastes without oxygen, and a second compartment, for polymer synthesis by enriched cultures of species with oxygen such as R. eutropha, P. oleovorans, or mixtures thereof. The compartments are integrated with barriers that permit mass transfer of organic acids while maintaining different culture conditions in the compartments.

A method for inexpensive and efficient PHA biosynthesis includes operating a sequencing bioreactor in alternating phases of nutrient deprivation and carbon feedstock deprivation to select for robust PHA-producing microbes. Preferably, the bioreactor is operated in a non-sterile manner with mixed cultures of methanotrophs. The method also preferably uses periodic biomass-wasting (PHA harvesting) at the end of the carbon feed phase, gradually lengthening the time period of carbon deprivation phase to create a penalty for rapid PHA degradation and incentive for PHA accumulation. Also, bacterial enrichment cultures may be introduced periodically. The PHA-accumulating bacteria are preferably grown on common anaerobic degradation products, specifically volatile fatty acids, such as acetate and propionate, and methane gas. The PHA has useful applications in bioplastics and other products.

The present invention provides a method to efficiently degrade nucleic acids, which result in a viscosity increase of the solution thereof on the occasion of decomposition or solubilization of microbial cells, in an easy and simple manner in the step of recovering various useful substance produced by a microorganism, and a use thereof. The product recovery method of the present invention make the product recovery from within microbial cells with ease under relatively mild conditions, because, by bringing living microbial cells into contact with a little amount of hypochlorous acid or a salt thereof, autodigestion of nucleic acids is induced and following decomposition of microbial cells or viscosity increase of the solution thereof after dissolution is inhibited. The method of the present invention is particularly preferred in recovering polyhydroxyalkanoates, which are biodegradable polymers, from microbial cells.

Methods are provided for producing biodegradable polyhydroxyalkanoates (PHAs) with desired geometry, molecular mass, mechanical and / or physical-chemical properties from glycerol, an inexpensive carbon source and byproduct of the biodiesel industry. Microorganisms capable of converting carbon to PHA can be used to convert biodiesel-glycerol to poly-3-hydroxybutyrate (PHB) or other monomer or copolymer PHAs via fermentation. The microorganisms are cultured in a medium comprising glycerol as a primary carbon source and one or more low molecular mass organic acids as a secondary carbon source. Biomass can be harvested from the culture medium and crude PHA extracted and purified, thereby recovering purified PHA with the desired property. After PHA isolation, a nucleating agent can be added to improve certain physical-chemical properties of the PHA, e.g., crystallization temperature, to enhance performance of the PHA during injection molding.