POLYHYDROXYALKANOATE PRODUCTION METHODS AND MATERIALS AND MICROORGANISMS USED IN SAME

摘要

Embodiments of the invention relate generally to methods to generate microorganisms and/or microorganism cultures that exhibit the ability to produce polyhydroxyalkanoates (PHA) from carbon sources at high efficiencies. In several embodiments, preferential expression of, or preferential growth of microorganisms utilizing certain metabolic pathways, enables the high efficiency PHA production from carbon-containing gases or materials. Several embodiments relate to the microorganism cultures, and/or microorganisms isolated therefrom.

主权项

1. A method for enhancing polyhydroxyalkanoate (PHA) generation in a methanotrophic culture by reducing copper concentrations to effect particulate methane monooxygenase (pMMO) production, the method comprising:
(a) contacting a culture of methanotrophic microorganisms with a medium comprising copper, one or more additional nutrients, and a carbon-containing gas that can be metabolized by said culture; (b) incubating said culture in said medium to cause growth of said culture; and (c) inducing a selection pressure in said culture to transform said culture into a culture that generates PHA preferentially through pMMO by:
(i) reducing the concentration of copper in said medium to cause production of soluble methane monooxygenase (sMMO) and/or particulate methane monooxygenase by said culture,wherein said concentration of copper causes the production of sMMO in some methanotrophic microorganisms;(ii) reducing the concentration of one or more said nutrient in said medium to cause said culture to generate PHA from said carbon-containing gas using said sMMO or said pMMO,wherein PHA is generated by pMMO at a greater rate as compared to sMMO,(iii) returning the culture to the growth conditions of step (b),wherein microorganisms having higher intracellular concentrations of pMMO and PHA grow at a greater rate as compared to those with lower intracellular pMMO and PHA concentrations; and(iv) repeating steps (ii) and (iii), wherein said repetitions selectively favor growth of microorganisms that produce PHA via pMMO, thereby facilitating the pMMO-mediated production of PHA at reduced copper concentrations, and resulting in a culture comprising essentially only microorganisms that use pMMO to produce PHA.