A semi-closed loop microalgal biomass production-platform for ethanol from renewable sources of nitrogen and phosphorous

JOURNAL OF CLEANER PRODUCTION

卷:219

Article

Sanchez Rizza, Lara ; Coronel, Camila D. ; Sanz Smachetti, Maria E. ; Do Nascimento, Mauro ; Curatti, Leonardo

关键词: Ethanol;    Feed;    Biological N-2-fixation;    Bone meal;    Sulfuric acid;   

DOI  :  10.1016/j.jclepro.2019.01.311

来源: Elsevier

【 摘 要 】

Production of microalgal biomass for feed and fuels demands unsustainable large amounts of fertilizers. The most broadly considered alternative sources of nutrients/fertilizer for microalgae are wastewater and internal recycling in closed-loop production platforms. However, these strategies largely disable co-production of feed and fuel in biomass biorefineries for an increased economic and environmental feasibility. In this study, we aimed at providing proof-of-concept for a semi-closed loop microalgal production-platform and biomass biorefinery for ethanol and feed from renewable resources of N and P. Atmospheric N-2 was assimilated into a N-2-fixing cyanobacterial biomass, which sustained growth of a microalga that accumulated high levels of carbohydrates (up to 60% (w/w)) as a sole source of fertilizer. The microalgal biomass was efficiently saccharified with H2SO4, which was recycled to release soluble PO4 from bone meal as a renewable source of P. Fermenting these P-enriched preparations with yeasts quantitatively produced ethanol at theoretical yields, a concentration of up to 50 g ethanol. L-1 and a yield of 0.25 g ethanol. g biomass(-1). Calculations suggested a potential yield from 7600 to 10,800 L ethanol. ha(-1). year(-1), under Buenos Aires environmental conditions, which would be higher than that currently obtained from maize feedstocks. The residual fermentation vinasse, supplemented with P and containing other downstream-process reagents, was recycled as a sole source of macronutrients for the cultivation of the N-2-fixing cyanobacterium to close the production cycle. Water recycling and co-production of residual biomass enriched in fat and protein as potential feed are also shown. This semi-closed loop biomass production-platform reconciles the concepts of microalgal biomass bio-refineries for the co-production of feedstocks for biofuels and feed and nutrients recycling in closed-loop systems that largely minimizes production of waste. (C) 2019 Elsevier Ltd. All rights reserved.

【 授权许可】

Free