The present disclosure is directed to medium chain length polyhydroxyalkanoate (mcl-PHA) copolymers, and to chewing gum bases and chewing gums comprising the mcl-PHA copolymers. In some instances, the mcl-PHA copolymers may partially or completely replace conventional petroleum-based gum base polymers, including elastomers, in the chewing gum and gum base. The chewing gums and gum bases of the present disclosure may be free or substantially free of petroleum-based ingredients. Chewing gums comprising the mcl-PHA copolymers of the present disclosure may also have enhanced degradability as compared to conventional chewing gums.

A method for producing PHA polymer includes using bacteria in which the bacteria are grown under heterotrophic conditions using an organic substance as carbon source and exponential growth conditions. The bacteria are then cultivated under autotrophic conditions under an atmosphere of H.sub.2, CO.sub.2 and O.sub.2, wherein the O.sub.2 content is less than 10% (v/v) and the pressure is more than 1 barg.

A method for producing PHA polymer includes using bacteria in which the bacteria are grown under heterotrophic conditions using an organic substance as carbon source and exponential growth conditions. The bacteria are then cultivated under autotrophic conditions under an atmosphere of H.sub.2, CO.sub.2 and O.sub.2, wherein the O.sub.2 content is less than 10% (v/v) and the pressure is more than 1 barg.

Culturing S. glucoliberatum PABB004 under conditions effective for the S. glucoliberatum PABB004 to secrete simple sugars into culture medium. In one or more embodiments, the conditions include a pH of 6.0 to 8.5. In some cases, the culture can include a second organism. A co-culture includes S. glucoliberatum PABB004 and a second organism, wherein the co-culture has a pH of 6.0 or greater. In one or more embodiments, the second organism is selected to produce a product of interest such as, for example, ethanol.

Methods and systems for producing prescribed unit size poly(3-hydroxyalkanoate) (PHA) polymers and copolymers are provided. The methods and systems can employ recombinant bacteria that are not native producers of PHA or lack enzymes to degrade PHA once synthesized, metabolize short to long chain fatty acids without induction, and express an (R)-specific enoyl-CoA hydratase and a PHA synthase, the (R)-specific enoyl-CoA hydratase and PHA synthase having wide substrate specificities. The recombinant bacteria are fed at least one fatty acid substrate that is equal in carbon length to the prescribed or desired unit size of the PHA polymer to be produced. The prescribed unit size PHA that is produced is then isolated and/or purified.

The present disclosure describes, in part, an enzyme-mediated radical initiating system and methods of using the system to produce polymers, including polymeric hydrogels, at ambient conditions.

The present disclosure describes, in part, an enzyme-mediated radical initiating system and methods of using the system to produce polymers, including polymeric hydrogels, at ambient conditions.

Provided herein are methods for generating cellular biomass in continuous aerobic fermentation systems. The biomass yield, and the concentration of polyhydroxyalkanoate within the biomass, are each directed to advantageous levels by operating the continuous fermentation system under particular nutrient limitation conditions. Also provided are biomass produced using the provided methods, and animal feed compositions including the provided biomass.

Provided herein are methods for generating cellular biomass in continuous aerobic fermentation systems. The biomass yield, and the concentration of polyhydroxyalkanoate within the biomass, are each directed to advantageous levels by operating the continuous fermentation system under particular nutrient limitation conditions. Also provided are biomass produced using the provided methods, and animal feed compositions including the provided biomass.

Disclosed is a mutant strain having the ability to produce polyhydroxybutyrate. The novel strain has a significantly high growth rate and an improved ability to produce PHB compared to existing PHB-producing cyanobacterial strains. Therefore, the novel strain is suitable for use in the production of PHB and the development of various products using PHB. In addition, the novel strain is useful as a photosynthetic strain for developing a PHB production process using industrial flue gas due to its ability to produce PHB from only CO.sub.2 without any additional organic carbon source. Also disclosed is a method for producing polyhydroxybutyrate using the mutant strain.