Life Cycle Impacts of Enzyme Production: Xylanase Production Case Study via Solid-state Fermentation and Suspended Culture Methods

Abstract

Xylanase enzyme has the potential to be used in bread production, as addition of small amounts of xylanase can significantly increase the volume of the bread, making it more appealing to the consumer. In this study, the environmental life cycle assessment of producing xylanase via suspended culture and solid-state fermentation methods has been realized by using CCaLC software with Ecoinvent 2 database and CML2001 method and the following impacts were calculated: carbon footprint, acidification potential, eutrophication potential, ozone layer depletion potential, photochemical smog potential, and human toxicity potential. Raw material acquisition, production, and transportation stages were taken into account. Results show that solid-state fermentation method has much higher environmental impact than the suspended culture method, mostly because of the higher yield of the latter. Energy consumption in the bioreactor stage, followed by high amounts of water use in separation and cleaning processes emerged as the main hotspots. The results showed consistency with earlier literature for high-purity enzyme production. An analysis of the potential implications of the nation-wide use of xylanase in bread production in Turkey showed that xylanase can increase the carbon footprint of bread production by 20% on average (of the two methods).