Harvesting of Arthrospira platensis with helicoidal and straight trichomes using filtration and centrifugation

Long-Term Cultivation of a Native Arthrospira platensis (Spirulina) Strain in Pozo Izquierdo (Gran Canaria, Spain): Technical Evidence for a Viable Production of Food-Grade Biomass

“…Harvesting efficiency of A. platensis BEA 1257B at a constant flow rate of 750 L/h onto a vibrating 40 µm stainless-steel net with 0.5 m 2 surface is reported in Table A2, Appendix B. Filter retention varied between 74.4 ± 4.7 and 82.1 ± 2.8% (mean value: 78.7 ± 3.3%), which is in line with the values reported for vibrating screens and for static woven nylon filters of the same mesh size operated with Arthrospira [26,37]. Conversely, the constant filtration flux applied in this study (1.5 m 3 /m 2 /h, limited by the technical characteristics of the pump) was approximately three times lower than those reported in the previous studies [26,37]. The harvesting efficiency depended on the culture densities (r = 0.99, p < 0.01), as a result of the partial clogging of the filter occurring at high cell concentration.…”

“…During F phase, harvesting parameters were determined as follows: Filtration flux was determined as the volume of culture passing the filter area over time [37]:…”

“…Harvesting efficiency (HE), i.e., the percentage of the biomass that was retained from the filter during harvesting, was determined by comparing the A. platensis concentration in the filtrate with that in the culture [37]. Dry weight content of the algal slurry (DW) was determined by drying a known amount of sample in aluminium trays overnight at 105 • C. Using these data, the concentration factor of the filtration was determined as the ratio of the dry weight in the algal slurry and the biomass concentration of the initial culture:…”

Current and novel approaches to downstream processing of microalgae: A review

“…For example, linear A. platensis filaments could be harvested at around 85% efficiency at 4000 x g for 10 min, in a laboratoryscale fixed angle rotor centrifuge. In contrast helical A. platensis filaments showed poor harvesting yield (around 50%) even at 9000 x g (Cuellar-Bermudez et al, 2019). S. obliquus cells could be removed from the culture by centrifugation at 3000 x g for 10 min, in a 750W TD5A centrifuge, with a harvest efficiency of 99.3% (Wang et al, 2019).…”

“…Gravity-driven dead-end filtration through 5 μm nylon membranes was enough to achieve > 90% harvesting efficiency of A. platensis cultures. Pumped filtration additionally increased the filtration flux up to 20 m 3 m −2 h −1 enabling a faster process (Cuellar-Bermudez et al, 2019). The flux of typical membrane filtration processes can be considerably smaller.…”