Novel biorefinery supply chains for wastewater valorization and production of high market value bio products using microalgae

Microalgae are a group of aquatic, photosynthetic microorganisms. They are characterized by fast growth rates and ability to survive in harsh conditions. Microalgae can be encountered in almost every ecosystem, from deserts [1] to arctic ones [2]. Thousands of different algae species are presumed to exist, with estimates reaching up to 72,500 [3]. So far, only 44,000 have been described [4]. Microalgae have attracted considerable research interest due to their metabolic pathways which generate multiple products of research interest such pigments, lipids, proteins and others [5]. 

Two main zones can typically be distinguished in a microalgae processing facility and in the research field in general. The first one is the upstream sector and refers to the selection of the appropriate microalgae strain and optimal cultivation. In the second zone, known also as downstream the activities of harvesting, pre-treatment, product extraction and refinement are grouped together [6].

Microalgae research mainly comprises of upstream, midstream, and downstream processes. Upstream processing focuses on microalgal cultivation and maximization of biomass production. Midstream processing aims to harvest microalgae from cultivation media, dry the collected biomass, and rupture the microalgal cell walls before the extraction process. Downstream processing targets the extraction and purification of the bioproduct(s) from microalgal biomass (Manirafasha et al., 2016).