Life cycle energy and greenhouse gas profile of a process for the production of ammonium sulfate from nitrogen-fixing photosynthetic cyanobacteria

• Main Author: Razon, Luis F.
• Format: text
• Published: Animo Repository 2012
• Subjects: Nitrogen—Fixation; Anabaena; Cyanobacteria; Greenhouse gas mitigation; Life cycles (Biology); Chemical Engineering
• Online Access: https://animorepository.dlsu.edu.ph/faculty_research/1641; https://animorepository.dlsu.edu.ph/context/faculty_research/article/2640/type/native/viewcontent
• Institution: De La Salle University

In this paper, an alternative means for nitrogen fixation that may consume less energy and release less greenhouse gases than the Haber-Bosch process is explored. A life-cycle assessment was conducted on a process to: culture the cyanobacterium, Anabaena sp. ATCC 33047, in open ponds; harvest the biomass and exopolysaccharides and convert these to biogas; strip and convert the ammonia from the biogas residue to ammonium sulfate; dry the ammonium sulfate solution to ammonium sulfate crystals and transport the finished product. The results suggest that substantial reductions in non-renewable energy use and greenhouse gas emissions may be realized. The study opens the possibility that Haber-Bosch ammonia may be replaced with ammonia from a biomass process which simultaneously generates renewable energy. The process is intrinsically safer than the Haber-Bosch process. However, there are trade-offs in terms of land use and possibly, water. © 2011 Elsevier Ltd.