Inexpensive non-toxic flocculation of microalgae contradicts theories; overcoming a major hurdle to bulk algal production

Schlesinger, Ami; Eisenstadt, Doron; Bar-Gil, Amicam; Carmely, Hilla; Einbinder, Shai; Gressel, Jonathan

doi:10.1016/j.biotechadv.2012.01.011

Cited by 214 publications

(113 citation statements)

References 30 publications

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“…Little is known about the cell wall of Nannochloropsis, though it is likely decorated with polysaccharides. Aggregation via charge neutralization with divalent cations has been hypothesized in other studies in which bacteria were found to be involved in aggregation (20) and in which algal autoflocculation in response to calcium was studied (23). The underlying mechanism of aggregation by RP1137 is likely similar to that of another bacillus, Paenibacillus kribbensis, the aggregation potential of which was also correlated with higher pH and the presence of calcium (15,17).…”

Section: Discussionmentioning

confidence: 84%

Rapid Aggregation of Biofuel-Producing Algae by the Bacterium Bacillus sp. Strain RP1137

Powell

Hill

2013

Appl Environ Microbiol

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Algal biofuels represent one of the most promising means of sustainably replacing liquid fuels. However, significant challenges remain before alga-based fuels become competitive with fossil fuels. One of the largest challenges is the ability to harvest the algae in an economical and low-energy manner. In this article, we describe the isolation of a bacterial strain, Bacillus sp. strain RP1137, which can rapidly aggregate several algae that are candidates for biofuel production, including a Nannochloropsis sp. This bacterium aggregates algae in a pH-dependent and reversible manner and retains its aggregation ability after paraformaldehyde fixation, opening the possibility for reuse of the cells. The optimal ratio of bacteria to algae is described, as is the robustness of aggregation at different salinities and temperatures. Aggregation is dependent on the presence of calcium or magnesium ions. The efficiency of aggregation of Nannochloropsis oceanica IMET1 is between 70 and 95% and is comparable to that obtained by other means of harvest; however, the rate of harvest is fast, with aggregates forming in 30 s.

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Section: Discussionmentioning

confidence: 84%

Rapid Aggregation of Biofuel-Producing Algae by the Bacterium Bacillus sp. Strain RP1137

Powell

Hill

2013

Appl Environ Microbiol

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“…Schlesinger et al reported that major hurdle to bulk algal production and harvesting can be tackled by non-toxic inexpensive alkaline flocculation. It is observed that the flocculent amount is governed by a function of logarithm of cell density and in dense cultures like biodigestable sludge, it should reduce the cost of the flocculation below $1.00 per 1000 kg of algal biomass [72].…”

Section: Harvesting and Processing Of Algaementioning

confidence: 99%

Microalgae as Future Fuel: Real Opportunities and Challenges

Sharma¹,

Thukral²,

Soni³

et al. 2015

J Thermodyn Catal

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“…Wu et al [8] explained that Mg(OH)2 precipitate coagulated microalgal cells by sweeping flocculation and charge neutralization. However, Schlesinger et al [10] found flocculation is not related to co-precipitation with iron, magnesium, phosphate or Ca(OH)2. Flocculation is still probably related to cell characteristics.…”

Section: +mentioning

confidence: 99%

“…By starving the cultures of CO2 just prior to harvest, it is possible to reduce NaOH additive amount. Schlesinger et al [10] reported this operation would halve the amount of Ca(OH)2 needed to induce flocculation when used Ca(OH)2 as a type of alkaline flocculant. …”

Section: Starving the Cultures Of Co2 Prior To Harvestmentioning

confidence: 99%

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Optimization of Alkaline Flocculation for Harvesting of Scenedesmus quadricauda #507 and Chaetoceros muelleri #862

et al. 2014

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A response surface methodology (RSM) was used to evaluate the effects of pH and microalgal biomass concentration (BC) on alkaline flocculating activity for harvesting one freshwater green algae Scenedesmus quadricauda #507 and one marine diatom Chaetoceros muelleri #862. The pH value and BC were in range of 9.0-12.0 and 0.20-2.30 g/L, respectively. Very high regression coefficient between the variables and the response indicates excellent evaluation of experimental data by second-order regressions. Optimum conditions for flocculating activity were estimated as follows: (i) pH 11.6, BC 0.54 g/L for strain #507 and (ii) pH 11.5, BC 0.42 g/L for strain #862. The maximum flocculating activity was around 94.7% and 100%, respectively. Furthermore, the addition of synthetic ocean water (SOW) to the freshwater #507 culture can increase the flocculating activity from 82.13%-88.79% in low algae concentration (0.52 g/L) and 82.92%-95.60% in high concentration (2.66 g/L).

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Inexpensive non-toxic flocculation of microalgae contradicts theories; overcoming a major hurdle to bulk algal production

Cited by 214 publications

References 30 publications

Rapid Aggregation of Biofuel-Producing Algae by the Bacterium Bacillus sp. Strain RP1137

Rapid Aggregation of Biofuel-Producing Algae by the Bacterium Bacillus sp. Strain RP1137

Microalgae as Future Fuel: Real Opportunities and Challenges

Optimization of Alkaline Flocculation for Harvesting of Scenedesmus quadricauda #507 and Chaetoceros muelleri #862

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