Environmental impacts on commercial microalgae-based products: Sustainability metrics and indicators

Abstract

Herein, the environmental impact of commercial microalgae-based products was assessed. The whole dried biomass production by Chlorella vulgaris and Arthrospira platensis were evaluated under different cultivation configurations. Besides, pigments such as β-carotene, astaxanthin, and phycocyanin, by Dunaliella salina, Haematococcus pluvialis, and Arthrospira platensis, respectively, were also subjected to environmental analysis, as well as docosahexaenoic (DHA) and eicosapentaenoic (EPA) acids by Crypthecodinium cohnii, Nitzschia laevis, and Nannochloropsis oculata. These products were estimated by midpoint indicators through the nine impact categories and subsequently submitted to the normalization stage. Also, environmental critical points of the process were identified and discussed, focusing on the combined operations of dehydration and drying of biomass, as well as the central role of the energy footprint and the challenges of the transition from fossil energy to renewable matrices. Among the results found for whole dried biomass, the parameters that most influence the burdens are directly related to the energy requirements of the downstream processes. In intracellular microalgal products, the extraction stage and yield of the compounds are factors that most affect environmental performance. Additionally, this work provides quantitative numbers of sustainability indicators for microalgae projects considering the current stage of the technology. Therefore, the results found in this study are the first step found in the literature to identify environmental improvements in the consolidated biotechnological routes of microalgae.