The released polysaccharide of the cyanobacterium Aphanothece halophytica inhibits flocculation of the alga with ferric chloride

Chen, Li; Li, Pengfu; Liu, Zhili; Jiao, Qingcai

doi:10.1007/s10811-008-9371-z

Cited by 34 publications

(11 citation statements)

References 13 publications

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“…It has been reported that many microalgae release large amount of RPS during growth [31], and most RPS can interfere with flocculation due to their complexation with multivalent metal ions [26,32]. However, some RPS are helpful to flocculation owing to the bridging mechanism [33,34].…”

Section: Resultsmentioning

confidence: 99%

Freshwater microalgae harvested via flocculation induced by pH decrease

Liu

Zhu

Tao

et al. 2013

Biotechnol Biofuels

174

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BackgroundRecent studies have demonstrated that microalga has been widely regarded as one of the most promising raw materials of biofuels. However, lack of an economical, efficient and convenient method to harvest microalgae is a bottleneck to boost their full-scale application. Many methods of harvesting microalgae, including mechanical, electrical, biological and chemical based, have been studied to overcome this hurdle.ResultsA new flocculation method induced by decreasing pH value of growth medium was developed for harvesting freshwater microalgae. The flocculation efficiencies were as high as 90% for Chlorococcum nivale, Chlorococcum ellipsoideum and Scenedesmus sp. with high biomass concentrations (>1g/L). The optimum flocculation efficiency was achieved at pH 4.0. The flocculation mechanism could be that the carboxylate ions of organic matters adhering on microalgal cells accepted protons when pH decreases and the negative charges were neutralized, resulting in disruption of the dispersing stability of cells and subsequent flocculation of cells. A linear correlation between biomass concentration and acid dosage was observed. Furthermore, viability of flocculated cells was determined by Evans Blue assay and few cells were found to be damaged with pH decrease. After neutralizing pH and adding nutrients to the flocculated medium, microalgae were proved to maintain a similar growth yield in the flocculated medium comparing with that in the fresh medium. The recycling of medium could contribute to the economical production from algae to biodiesel.ConclusionsThe study provided an economical, efficient and convenient method to harvest fresh microalgae. Advantages include capability of treating high cell biomass concentrations (>1g/L), excellent flocculation efficiencies (≥ 90%), operational simplicity, low cost and recycling of medium. It has shown the potential to overcome the hurdle of harvesting microalgae to promote full-scale application to biofuels from microalgae.

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Section: Resultsmentioning

confidence: 99%

Freshwater microalgae harvested via flocculation induced by pH decrease

Liu

Zhu

Tao

et al. 2013

Biotechnol Biofuels

174

View full text Add to dashboard Cite

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“…It has been reported that RPS may interfere with flocculation due to their complexation with multivalent metal ions (Chen et al, 2008;Wu et al, 2012) or be helpful to flocculation owing to the bridging mechanism (Passow and Alldredge, 1995;Shipina et al, 1999). In our previous report, RPS of the self-flocculating microalgae plays negligible role in the pH-decrease induced flocculation process (Liu et al, 2013).…”

Section: Effect Of Rps In Flocculation Processmentioning

confidence: 80%

Effective flocculation of target microalgae with self-flocculating microalgae induced by pH decrease

Liu

Tao

et al. 2014

Bioresource Technology

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“…Thus, a much larger amount of coagulant would be consumed to enable protein complexation, which was unavailable for cell removal. The AOM of M. aeruginosa consumes coagulants in the coagulation process because of the formation of chelate complexes with the coagulant (Chen et al 2009;Takaara et al 2010). Hence, the AOM was simultaneously removed during the coagulation process.…”

Section: Resultsmentioning

confidence: 99%

Flocculation of Microcystis aeruginosa by steel slag and its safety evaluation

Cao

Zhang

et al. 2015

J Appl Phycol

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This study investigated the flocculation of Microcystis aeruginosa by steel slag and evaluated the safety of treated water. The results showed that algal cells at a steel slag dosage of 0.48 g L −1 were effectively removed from two diluted algal solutions when their algogenic organic matter (AOM) contents were 3.54 and 5.81 mg L −1 (referred to as S1 and S2) with algae removal rates of 93.8 and 92.6 %, respectively. Simultaneously, the concentrations of AOM were reduced in S1 and S2 with removal efficiencies of 72.6 and 70.2 %, respectively. Charge neutralisation and bridging were probably the mechanisms that accelerated the flocculation processes. However, AOM had a priority over the algae in the reaction with the steel slag by producing protein complexation, which adversely affected coagulation and increased coagulant demand. Increased K + and AOM after flocculation indicated that cell damage occurred at a retention time of 36 h. However, acute toxicity test demonstrated that the inhibition rate did not significantly increase until the retention time reached 48 h. Overall, steel slag has a great potential as a low-cost alternative to control algal bloom and restore aquatic ecosystems.

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The released polysaccharide of the cyanobacterium Aphanothece halophytica inhibits flocculation of the alga with ferric chloride

Cited by 34 publications

References 13 publications

Freshwater microalgae harvested via flocculation induced by pH decrease

Freshwater microalgae harvested via flocculation induced by pH decrease

Effective flocculation of target microalgae with self-flocculating microalgae induced by pH decrease

Flocculation of Microcystis aeruginosa by steel slag and its safety evaluation

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