Bio-plastics production from industrial waste streams in membrane bioreactors

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Bio-plastics production to displace petrochemical based polymers is emerging as an important research and commercial area due to a variety of reasons including the need for renewable and biodegradable chemicals, rural economic development, environmental sustainability, and waste management. Canada has abundant industrial and agricultural waste streams rich in carbon, which are prime feedstock targets for bio-polymer synthesis. Polyhydroxyalkanoates (PHAs) are a group of polymers that can be produced through bacterial fermentation and are of industrial and commercial interest, as they can replace fossil-fuel based polyesters and are biodegradable. A sub-group of PHAs, those with carbon chain lengths of 6-14 termed medium chain length PHAs (mcl-PHAs) have a high commercial value due to their favorable thermoplastic properties. The most important factors affecting the overall economics of PHA production are PHA productivity (mass of PHA produced/reactor volume/time) and cost of raw materials. This research aims to make significant progress on both these fronts. Pure chemical feedstock will be replaced by industrial waste streams from potato processing (waste oils) and biodiesel production (waste glycerol) plants. We will explore bacterial fermentation methods to maximize the production of mcl-PHAs from these waste sources. We will determine the concentration and composition of the PHAs produced and assess its potential commercial value. The volumetric productivity of PHAs can be increased substantially when switching from a batch or semi-batch feed operation to a continuous-feed operation. We will use a Membrane Bioreactor (MBR) system for continuous-feed fermentation to increase volumetric productivity, decrease production footprint, provide consistent product quality, and reduce production down-time. This will mark the first time MBR systems (commonly used for waste water treatment) will be evaluated for the production of mcl-PHAs from industrial waste streams. This research will support the growing bio-refining industry in Canada, furthering the existing scientific knowledge base and providing a new alternative production system for industrial application.