Production and Conversion of Biorefinery Cellulose to Advanced Fuels, Biochemicals and Biomaterials

Lead Proponent:  Lignol Innovations Ltd.
Location:  Burnaby, BC
ecoEII Contribution:  $ 1,100,000
Project Total:  $ 2,630,000

Project Background :

One of the most critical steps of all cellulosic biorefinery processes is the hydrolysis of the cellulosic substrate into fermentable sugars by the addition of enzymes.   Despite recent advancements in enzyme technologies, the current enzymatic hydrolysis processes are still viewed, in general, as too costly due to a combination of slow conversion rates, high dosages and high enzyme price.

To overcome this hurdle, Lignol, a biorefinery technology company, developed a novel enzymatic hydrolysis (EH) process which has the potential to increase enzyme effectiveness (i.e. lower the cost of sugar) and at the same time, produce a unique co-product that has higher economic value.

EcoEII awarded $1,100K towards Lignol’s project “Production and Conversion of Biorefinery Cellulose to Advanced Fuels, Biochemicals and Biomaterials” to investigate and confirm the novel EH process at lab scale, as well as the potential for the production of valuable co-products.

Results:

The enzyme dosage and sugar release relationship for three benchmark substrates: aspen, lodgepole pine and wheat straw were evaluated.  Two enzyme preparations from Novozymes were used at varying dosages and combinations.  Through a series of trials, enzyme dosage for the novel EH process was optimized.  It was determined that the EH process reduces enzyme cost (on a per unit sugar released basis) from 40% to 65% (as compared to the base case), depending on the biomass feedstock. 

Effective solid/liquid separation after the EH process, and the net recovery of sugars was the next challenge.  In order to achieve the desired sugar recovery of >65%, a number of washing sequences were examined.  It was determined that the optimum washing sequence involved four individual steps, and achieved 80-85% sugar recovery for the three substrates.  The resulting sugars obtained from the aspen and lodgepole pine were effectively converted to bio-succinic acid.  The yield of bio-succinic acid on the glucose consumed was essentially the same as that was achieved using lab grade glucose (control). The sugar solutions were not successfully fermented to lipids using engineered microorganisms.

Moreover, five additional processing schemes were tested to enhance the fibre quality of the cellulose residue (after EH treatment).   It was concluded that after post-treatment both the aspen and lodgepole pine substrates had properties that would likely be suitable for the production of Man Made Cellulose Fibres (MMCF) such as rayon or viscose. To confirm this assessment, samples would have to be provided to a commercial MMCF producer.

A preliminary economic analysis showed that these enhancements have the potential to improve the internal rate of return of a nominal 1,000 tpd commercial project by more than 50% over the base case. The combination of enzyme dosage reduction along with effective sugar recovery, confirmed that the novel EH process was a viable addition to Lignol’s biorefinery technology.

Benefits to Canada:

Despite vast biomass resources in Canada, the conversion of cellulose to fermentable sugars has been a major techno-economic challenge that hinders commercial scale production of cellulosic biofuels.  The Project addressed this technology gap by investigating and evaluating a novel enzymatic hydrolysis (EH) step which would increase the efficiency of the saccharification process and thereby reduce the cost of producing cellulosic sugars.  Improving the internal rate of return should also allow profitable biorefineries to be built at a smaller scale, with lower capital outlay.

Next Steps:

The technology developed is being considered for integration into a number of the early-stage projects being developed by Lignol and its partners.  Further work beyond the laboratory scale is needed prior to full commercialization.

Please contact the ecoENERGY program to obtain a copy of Lignol Innovations Completion Report.