Flocculation properties of several microalgae and a cyanobacterium species during ferric chloride, chitosan and alkaline flocculation

Abstract

Flocculation properties of several microalgae and a cyanobacterium species during ferric chloride, chitosan and alkaline flocculation, Bioresource Technology (2016), doi: http://dx.doi.org/10.1016/j.biortech.2016.08.080 Archived versionAuthor manuscript: the content is identical to the content of the published paper, but without the final typesetting by the publisher This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. 28Flocculation holds great potential as a low-cost harvesting method for microalgae biomass 29 production. Three flocculation methods (ferric chloride, chitosan, and alkaline flocculation) were 30 compared in this study for the harvesting of 9 different freshwater and marine microalgae and one 31 cyanobacterium species. Ferric chloride resulted in a separation efficiency greater than 90% with a 32 concentration factor (CF) higher than 10 for all species. Chitosan flocculation worked generally 33 very well for freshwater microalgae, but not for marine species. Alkaline flocculation was most 34 efficient for harvesting of Nannochloropsis, Chlamydomonas and Chlorella sp. The concentration 35 factor was highly variable between microalgae species. Generally, minimum flocculant dosages 36 were highly variable across species, which shows that flocculation may be a good harvesting 37 method for some species but not for others. This study shows that microalgae and cyanobacteria 38 species should not be selected solely based on their productivity but also on their potential for low-39 cost separation. 47• high variation in optimal dosages between species and flocculation methods 48• chitosan was ineffective for harvesting marine species 49• species selection for low-cost separation is important 50 51 52 3 53

Cyanobacteria as an eco‐friendly resource for biofuel production: A critical review

“…Flocculation is an economical method for biomass recovery; however, usually, one method does not have a similar yield for different microalgae and cyanobacteria. Therefore, flocculant dosage is an important factor in the selection of the candidate cyanobacterial isolate to produce biofuel . Beside direct application of cyanobacteria for the biofuel production, they can be used as a feed supply for eukaryotic microalgae which can produce biodiesel feedstock.…”

“…Therefore, flocculant dosage is an important factor in the selection of the candidate cyanobacterial isolate to produce biofuel. 133 Beside direct application of cyanobacteria for the biofuel production, they can be used as a feed supply for eukaryotic microalgae which can produce biodiesel feedstock. Nascimento et al 134 indicated that the biomass of Nfertilizer cyanobacterium, Nostoc sp.…”

Efficient Harvesting of Nannochloropsis Microalgae via Optimized Chitosan‐Mediated Flocculation

“…Lama et al even showed that chitosan is not able to induce the formation of Nannochloropsis sp. flocs . As the chitosan was dissolved in acetic acid, the pH of the culture decreased to 6–7.…”

Synthesis and Characterization of Ampholytic Flocculant CPCTS-g-P (CTA-DMDAAC) and Its Flocculation Properties for Microcystis Aeruginosa Removal

“…The hydroxymethylation reaction occurred easily under neutral or alkaline condition, thereby resulting in a decrease in the intrinsic viscosity and the grafting efficiency of the polymer [38]. Meanwhile, the effect of hydrogen bonding was strengthened by the protonation of most carboxylic acids and quaternary ammonium groups in an acidic environment, thereby playing a negative role in improving the intrinsic viscosity of CPCTS-g-P (CTA-DMDAAC) [39]. Therefore, the optimal pH range is 4-6.…”