Microalgae as a Feedstock for Biofuel Precursors and Value-Added Products: Green Fuels and Golden Opportunities

Abstract

The prospects of biofuel production from microalgal carbohydrates and lipids coupled with greenhouse gas mitigation due to photosynthetic assimilation of CO2 have ushered in a renewed interest in algal feedstock. Furthermore, microalgae (including cyanobacteria) have become established as commercial sources of value-added biochemicals such as polyunsaturated fatty acids and carotenoid pigments used as antioxidants in nutritional supplements and cosmetics. This article presents a comprehensive synopsis of the metabolic basis for accumulating lipids as well as applicable methods of lipid and cellulose bioconversion and final applications of these natural or refined products from microalgal biomass. For lipids, one-step in situ transesterification offers a new and more accurate approach to quantify oil content. As a complement to microalgal oil fractions, the utilization of cellulosic biomass from microalgae to produce bioethanol by fermentation, biogas by anaerobic digestion, and bio-oil by hydrothermal liquefaction are discussed. Collectively, a compendium of information spanning green renewable fuels and value-added nutritional compounds is provided.

Novel insights into salinity-induced lipogenesis and carotenogenesis in the oleaginous astaxanthin-producing alga Chromochloris zofingiensis: a multi-omics study

“…Despite the progresses achieved during the past decades, challenges remain yet to be addressed for bringing down the production cost and realizing commercialization of algal biofuels [4][5][6]. Among the strategies proposed for addressing challenges, integrated production of lipids with value-added products from algae is believed to be promising to improve algal biofuel production economics [7]. These products include, but are not restricted to high-value proteins (e.g., phycobilins), ω-3 polyunsaturated fatty acids (e.g., eicosapentaenoic acid and docosahexaenoic acid), and carotenoids (e.g., β-carotene, fucoxanthin and astaxanthin), depending on the source of algal species/strains [7].…”

“…Among the strategies proposed for addressing challenges, integrated production of lipids with value-added products from algae is believed to be promising to improve algal biofuel production economics [7]. These products include, but are not restricted to high-value proteins (e.g., phycobilins), ω-3 polyunsaturated fatty acids (e.g., eicosapentaenoic acid and docosahexaenoic acid), and carotenoids (e.g., β-carotene, fucoxanthin and astaxanthin), depending on the source of algal species/strains [7]. It is worth noting that, from a biorefinery point of view, concurrent synthesis of value-added products and lipids by algae is a prerequisite for implementation of the integrated production concept.…”

A Short Review on the Valorization of Green Seaweeds and Ulvan: FEEDSTOCK for Chemicals and Biomaterials

“…For instance, seaweeds possess a high level of structural polysaccharides and low lignin contents. In addition to serving as feedstocks for biofuel production, green seaweeds are also an important source of high-value chemicals, such as polyunsaturated fatty acids, carotenoids, phycobilins, and polysaccharides [ 12 ]. Most importantly, green seaweeds are a cheap and important source for biomaterials.…”

Soda-anthraquinone pulping and cationization of Posidonia oceanica

“…Recently, seaweed and seagrass have been described as promising sources of cellulose due to their lack of (most algae) or low (sea plants) content of lignin in the cell wall (Knoshaug et al 2013;Syed et al 2016;Tang et al 2016). This is because lignification of the cell wall is the result of the evolution of land plants from sea species to give consistency to the cells of herbaceous and woody stalks (Peter and Neale 2004;Liitiä et al 2014).…”