Life cycle assessment of bacterial cellulose production

Abstract

Purpose Bacterial cellulose (BC), obtained by fermentation, is an innovative and promising material with a broad spectrum of potential applications. Despite the increasing efforts towards its industrialization, a deeper understanding of the environmental impact related to the BC production process is still required. This work aimed at quantifying the environmental, health, and resource depletion impacts related to a production of BC.

Methods An attributional life cycle assessment (LCA) was applied to a process design of production of BC, by static culture, following a cradle-to-gate approach. The LCA was modeled with GaBi Pro Software using the ReCiPe 2016 (H) methodology with environmental impact indicators at midpoint level. The functional unit was defined as 1 kg of BC (dry mass), in 138.8 kg of water.

Results From the total used resources (38.9 ton/kg of BC), water is the main one (36.1 ton/kg of BC), most of which (98%) is returned to fresh waters after treatment. The production of raw materials consumed 17.8 ton of water/kg of BC, 13.8 ton/kg of BC of which was for the production of carton packaging, culture medium raw materials, and sodium hydroxide (for the washing of BC). The remaining consumed water was mainly for the fermentation (3.9 ton/kg) and downstream process (7.7 ton/kg). From the identified potential environmental impacts, the production of raw materials had the highest impact, mainly on Climate change, Fossil depletion, Human toxicity, non-cancer, and Terrestrial toxicity. The sodium dihydrogen phosphate production, used in the culture medium, showed the highest environmental impacts in Human toxicity, non-cancer and Terrestrial ecotoxicity, followed by corn syrup and carton production. The static culture fermentation and downstream process showed impact in Climate change and Fossil depletion.

Conclusions Per se, the BC production process had a small contribution to the consumption of resources and environmental impact of the BC global life cycle.