Process Evaluation of Enzymatic Hydrolysis with Filtrate Recycle for the Production of High Concentration Sugars
- 236 Downloads
Process simulation and lab trials were carried out to demonstrate and confirm the efficiency of the concept that recycling hydrolysate at low total solid enzymatic hydrolysis is one of the options to increase the sugar concentration without mixing problems. Higher sugar concentration can reduce the capital cost for fermentation and distillation because of smaller retention volume. Meanwhile, operation cost will also decrease for less operating volume and less energy required for distillation. With the computer simulation, time and efforts can be saved to achieve the steady state of recycling process, which is the scenario for industrial production. This paper, to the best of our knowledge, is the first paper discussing steady-state saccharification with recycling of the filtrate form enzymatic hydrolysis to increase sugar concentration. Recycled enzymes in the filtrate (15–30% of the original enzyme loading) resulted in 5–10% higher carbohydrate conversion compared to the case in which recycled enzymes were denatured. The recycled hydrolysate yielded 10% higher carbohydrate conversion compared to pure sugar simulated hydrolysate at the same enzyme loading, which indicated hydrolysis by-products could boost enzymatic hydrolysis. The high sugar concentration (pure sugar simulated) showed inhibition effect, since about 15% decrease in carbohydrate conversion was observed compared with the case with no sugar added. The overall effect of hydrolysate recycling at WinGEMS simulated steady-state conditions with 5% total solids was increasing the sugar concentration from 35 to 141 g/l, while the carbohydrate conversion was 2% higher for recycling at steady state (87%) compared with no recycling strategy (85%). Ten percent and 15% total solid processes were also evaluated in this study.
KeywordsSteady state Process simulation Enzymatic hydrolysis Stream recycling Hydrolysis booster
This work was funded by the Wood-to-Ethanol Research Consortium (WERC). WERC members are American Process, Andritz, Arborgen, KBR Engineers, Catchlight, Evolution Resources, and Japan Pulp and Paper Research Institute. Enzymes were kindly provided by Novozymes and Genencor. The authors are grateful to these companies.
- 4.Johnson, D., & Elander, R. (2008). Pretreatments for enhanced digestibility of feedstocks in biomass recalcitrance. Oxford: Blackwell.Google Scholar
- 5.Carvalheiro, F., Duarte, L. C., & Gírio, F. M. (2008). Journal of Scientific and Industrial Research, 67, 849–864.Google Scholar
- 19.Ramos, L. P., & Saddler, J. N. (1994). Applied Biochemistry and Biotechnology, 193, 45–46.Google Scholar
- 22.TAPPI. (2004). T200 om-88, TAPPI test methods. Atlanta: TAPPI.Google Scholar
- 24.Oliveira, K., Cardoso, M., & Nicolato, R. (2010). Latin American Appl Research., 40, 81–90.Google Scholar
- 25.Atkins, M., Morrison, A., Walmsley, M., & Riley, J. (2010). Appita J., 63, 281–287.Google Scholar
- 26.Sigma-Aldrich. (2006). Sigma-Aldrich product information, Bradford reagent, product number B6916. Oakville: Sigma-Aldrich.Google Scholar
- 27.Sutcliffe, R., & Saddler, J. N. (1986). Biotechnology and Bioengineering, 17, 749–762.Google Scholar
- 28.Tan, L. U. L., Yu, E. K. C., Campbell, N., & Saddler, J. N. (1986). Applied Microbiology and Biotechnology, 25, 250–255.Google Scholar
- 34.Clark, T. A., & Mackie, K. L. (1984). Journal of Chemical Technology and Biotechnology, 34B, 101–110.Google Scholar
- 36.Quinlana, R. J., Sweeneya, M. D., Leggiob, L. L., Ottenb, H., Poulsenb, J. C. N., Johansenc, K. S., et al. (2011). PNAS, 44, 108–113.Google Scholar