Valorization of Negative-Cost Industrial Waste at the Forest Biorefinery

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The Forest Sector contributes 12% to the national GDP (CAD 58 billion) and is a major employer directly employing 235,000 Canadians across the country. However, due to the strong offshore competition, unstable oil prices and uncertainties about oil reserves, concerns about global warming, and global movement and incentives for green fuels and chemicals, the Canadian Forest Sector needs to diversify its products and markets, in order to create additional revenues and remain competitive. This can be accomplished by evolving the Canadian pulp and paper mills into Forest Biorefineries - processing and conversion facilities that fully integrate forest biomass and biomass waste for the simultaneous production of marketplace products, including pulp and paper, chemicals and energy. This NSERC Discovery grant has the objective to contribute to the development of the Forest Biorefinery by creating new value from the negative-cost biomass waste (primary and secondary sludge) that is available at Canadian pulp and paper mills. The sludge landfilling and incinerating is not economically and environmentally attractive due to the prohibitively high treatment costs and potential environmental harmfulness. This proposal aims at valorization of the sludge waste by converting it to fermentable sugars, lactic acid and polylactic acid (PLA). Lactic acid is widely used in the food industry and as a raw material for PLA, whereas PLA is a biodegradable polymer that can replace synthetic plastics in a variety of industrial applications. It is proposed to enzymatically decompose paper sludge to simple fermentable sugars first, followed by bioconversion of these sugars to lactic acid using a robust and highly-productive fermentation organism that will be additionally engineered for optimal performance. Different fermentation methods will be evaluated in batch, fed-batch, repeated and semi-continuous cultures for production of lactic acid. Following lactic acid production under optimized conditions, a new catalytic process will be designed that allows for PLA production without prior lactic acid purification. Expected benefits from the successful execution of this research program include: 1) Technical Benefits: Technology for conversion of waste streams generated at pulp and paper mills into value-added products of economic significance; 2) Economic Benefits: Reduced production costs, lower energy input and chemical consumption; 3) Environmental Benefits: Reduced waste generation, waste utilization, reduced greenhouse gas emissions; 4) Social and Education Benefits: Training of highly qualified workforce of scientists and engineers that will implement their skillsets for Canada’s future socio-economic growth and prosperity; high potential for new job creation in the manufacturing industry; new knowledge creation in the form of patents, publications, reports and presentations.