Bioflocculation as an innovative harvesting strategy for microalgae

Growing Chlorella vulgaris on mixed wastewaters for biodiesel feedstock production and nutrient removal

“…Microalgae are a potential feedstock for making biodiesel because of their unique advantages of fast growth, high oil content, not competing with arable land, synergy with CO 2 sequestration and wastewater treatment . However, the production cost of biodiesel from microalgae is usually higher than that from traditional oil crops owing to many constraints, such as the high cost of algae cultivation and harvesting . For algae cultivation, the large water footprint and nutrients demand are two of the major bottlenecks.…”

“…1,2 However, the production cost of biodiesel from microalgae is usually higher than that from traditional oil crops owing to many constraints, such as the high cost of algae cultivation and harvesting. 3 For algae cultivation, the large water footprint and nutrients demand are two of the major bottlenecks. For example, to produce 1 kg of biodiesel from microalgae, 3726 kg of water, 0.33 kg of nitrogen and 0.71 kg of phosphate are required.…”

Innovative harvesting processes for microalgae biomass production: A perspective from patent literature

“…Secondly, the chemical composition of the growth medium will affect harvesting efficiency (pH, nutrients, salinity, temperature, density). This is particularly true for flocculation and bioflocculation techniques [12]. A high salinity inhibits organic flocculation as well [29] but could improve electrolytic flocculation [41].…”

“…Chemical techniques make use of inorganic or organic additives to enhance coagulation, or for example (nano)particles with magnetic properties to neutralize the microalgal negative charge for coagulation [11]. Finally, concentration techniques that are based on biological processes to induce spontaneous or natural flocculation, are generally referred to as bioflocculation [12]. These methods do not require additional chemicals but rely on interactions with bacteria, fungi or even with other microalgae species for co-flocculation.…”

Harvesting and cell disruption of microalgae

“…For dilute cultivation systems (e.g. open ponds), flocculation is considered as a lowcost (pre-) concentration technology (Alam et al, 2016;Japar et al, 2017;Muylaert et al, 2015;Uduman et al, 2010;Vandamme et al, 2013). Flocculation of saltwater microalgae, however, is difficult, as most flocculants are not effective at high salinity (Greenwell et al, 2010;Uduman et al, 2010;Vandamme et al, 2013).…”