Harvesting of microalgae by flocculation with poly (γ-glutamic acid)

Zheng, Hongli; Gao, Zhen; Yin, Jinhua; XiaoHong, Tang; Ji, Xiao‐Jun; Huang, He

doi:10.1016/j.biortech.2012.02.086

Cited by 191 publications

(84 citation statements)

References 26 publications

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“…The chemicals that are commonly used as flocculants are inorganic salts like ferric chloride and aluminium sulphate (Rwehumbiza et al, 2012;Shen et al, 2013;Şirin et al, 2013;Wyatt et al, 2012). On the other hand, bioflocculants include biopolymers like chitosan, which comes from the deactylation of chitin from crab and shrimp shells (Farid et al, 2013;Şirin et al, 2013) and poly (γ-glutamic acid), an extracellular product from Bacillus subtilis (Zheng et al, 2012). Modern techniques involve creating new materials like nanoparticles (Farid et al, 2013), magnetic particles (Hu et al, 2013;Prochazkova et al, 2013), cationic polymers (Roselet et al, 2016;Vandamme et al, 2010), polymer composites (Hena et al, 2016), and even combinations of these materials (Hu et al, 2014).…”

Section: Harvesting Of Nannochloropsis Biomassmentioning

confidence: 99%

A biorefinery for Nannochloropsis: Induction, harvesting, and extraction of EPA-rich oil and high-value protein

Chua

Schenk

2017

Bioresource Technology

126

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Please cite this article as: Chua, E.T., Schenk, P.M., A biorefinery for Nannochloropsis: induction, harvesting, and extraction of EPA-rich oil and high-value protein, Bioresource Technology (2017), doi: http://dx.doi.org/10. 1016/ j.biortech.2017.05.124 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. AbstractMicroalgae have been studied as biofactories for almost four decades. Yet, even until today, many aspects of microalgae farming and processing are still considered exploratory because of the uniqueness of each microalgal species. Thus, it is important to develop the entire process of microalgae farming: from culturing to harvesting, and down to extracting the desired high-value products. Based on its rapid growth and high oil productivities, Nannochloropsis sp. is of particular interest to many industries for the production of highvalue oil containing omega-3 fatty acids, specifically eicosapentaenoic acid (EPA), but also several other products. This review compares the various techniques for induction, harvesting, and extraction of EPA-rich oil and high-value protein explored by academia and industry to develop a multi-product Nannochloropsis biorefinery. Knowledge gaps and opportunities are discussed for culturing and inducing fatty acid biosynthesis, biomass harvesting, and extracting EPA-rich oil and high-value protein from the biomass of Nannochloropsis sp.

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Section: Harvesting Of Nannochloropsis Biomassmentioning

confidence: 99%

A biorefinery for Nannochloropsis: Induction, harvesting, and extraction of EPA-rich oil and high-value protein

Chua

Schenk

2017

Bioresource Technology

126

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“…Several studies are available on the use of chemical flocculation using metal salts or polyelectrolytes (Gerde et al 2014;Granados et al 2012;Papazi et al 2010;Tenney et al 1969), pH induced flocculation (Vandamme et al 2012;Wu et al 2012;Zheng et al 2012), and bioflocculation using bacteria or filamentous fungi for biomass harvest (Zhou et al 2013). In electroflocculation, the flocculant is produced by releasing metal ions from a sacrificial electrode (Vandamme et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Effect of voltage and electrode material on electroflocculation of Scenedesmus acuminatus

Bleeke

Quante

Winckelmann

et al. 2015

Bioresour. Bioprocess.

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Background: Microalgae are a promising new source for biomass production. One of the major challenges in regards to cost effectiveness is the biomass harvest. High energy input is required for the separation of the small algal cells from a large volume of surrounding media. Electroflocculation is reported as a promising harvesting technique to improve cost effectiveness within the downstream process. In the present study, six electrode materials were tested for electroflocculation of Scenedesmus acuminatus. Besides the commonly used aluminum and iron electrodes, magnesium, copper, zinc and brass electrodes were tested for biomass harvest and compared. The influence of four different voltages (10, 20, 30 and 40 V) was investigated and evaluated. Results:Electroflocculation was applicable with all tested electrode materials. The highest flocculation efficiency was achieved using magnesium electrodes followed by Al, Zn, Cu, Fe and brass. Using magnesium, 90% of the suspension was clarified at 40, 30, 20, and 10 V after 9.2, 12.5, 18.5, and 43 min, respectively. All electrode materials showed the fastest flocculation at 40 V and the lowest at 10 V. The pH increased from 7.5 to values between 9.3 and 11.9 during the flocculation processes. Reuse of the supernatant showed no adverse effect on algal growth. The highest cell counts after 12 days of incubation were achieved with iron at 1.86 × 10 7 cells ml −1 and the lowest with copper at 1.23 × 10 7 cells ml −1. Conclusion:Besides the commonly used iron and/or aluminum electrodes, other materials like magnesium, copper, zinc and brass can be successfully used for microalgal biomass harvest. For special biomass applications like food or feed additives, metals like magnesium have other advantages besides their high flocculation efficiency such as their low toxicity at high concentrations. Higher voltages increased the maximum flocculation efficiency but also increased the required energy input.

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“…Plant-based natural coagulant is more environmental friendly and not pose health risks as chemical flocculants such as aluminum and ferric salts. The use of inorganic coagulants such as ferric chloride, FeCl 3 and aluminum sulfate, Al 2 (SO 4 ) 3 shortly known as alum is proven to be effective for some microalgae flocculation, however it is certainly unacceptable if the harvested biomass is to be used for aquaculture purposes, animal feed or organic fertilizer. It was reported that the major component of alum and acrylamide could lead to human health implications, such as involvement in Alzheimer's disease and the cause of cancers [2].…”

Section: Introductionmentioning

confidence: 99%

“…It was reported that the major component of alum and acrylamide could lead to human health implications, such as involvement in Alzheimer's disease and the cause of cancers [2]. According to Zheng et al [3], these flocculants are required in high doses, both are more than 0.75 g·L -1 for microalgae harvesting.…”

Section: Introductionmentioning

confidence: 99%

Moringa oleifera SEED DERIVATIVES AS POTENTIAL BIO-COAGULANT FOR MICROALGAE Chlorella Sp. HARVESTING

Endut¹,

Hajar²,

Hamid³

et al. 2016

MJAS

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Microalgae is an economical and potential raw material of biomass energy, which offer a wide range of commercial potential to produce valuable substances for applications in aquaculture feed, pharmaceutical purposes and biofuels production. However, lack of an economical, efficient and convenient method to harvest microalgae is a bottleneck to boost their full-scale application. Hence, this study was performed to investigate the potentialities of Moringa oleifera seed derivatives as an environmentally biocoagulant to harvest microalgae Chlorella sp. biomass from the water column, which acts as a binder to coagulate particulate impurities to form larger aggregates. Results shown M. oleifera to have better biomass recovery of 122.51% as compared to 37.08% of alum at similar dosages of 10 mg·L -1 . In addition, it was found that the zeta potential values of mixed microalgaecoagulant suspension shows positive correlation on the flocculation parameters. For biomass recovery, the correlation for M. oleifera protein powder showed the R 2 -value of 0.9565 whereas the control chemical flocculant, alum with the R 2 -value of 0.7920. It was evidence that M. oleifera has a great potential in efficient and economical for environmentally microalgae harvesting and the adaptation of biological harvesting technology especially for the purpose of aquaculture feed in Malaysia.Keywords: Chlorella sp., coagulation-flocculation, isoelectric point, Moringa oleifera, zeta potential Abstrak Mikroalga merupakan bahan mentah yang murah dan berpotensi untuk tenaga biojisim, yang menawarkan pelbagai peluang pengkomersialan untuk menghasilkan bahan bernilai untuk aplikasi dalam makanan akuakultur, farmaseutikal dan penghasilan bahan bakar bio. Walaubagaimanapun, kekurangan kaedah yang murah, cekap dan mudah untuk penuaian mikroalga merupakan halangan untuk meningkatkan aplikasi teknologi ini dalam skala yang lebih besar. Oleh itu, kajian ini telah dijalankan untuk menyiasat potensi derivatif biji Moringa oleifera sebagai bio-penggumpal biojisim mikroalga Chlorella sp., yang bertindak sebagai pengikat untuk menggumpalkan zarah enapcemar membentuk agregat yang lebih besar dari kolum air. Keputusan menunjukkan M. oleifera mempunyai pemulihan biojisim yang lebih baik iaitu 122.51% berbanding alum iaitu 37.08% pada dos yang sama sebanyak 10 mg·L -1 . Di samping itu, nilai keupayaan zeta campuran mikroalga dan penggumpal menunjukkan kolerasi positif terhadap parameter penggumpalan. Dalam pemulihan biojisim, kolerasi bagi serbuk protein M. oleifera menunjukkan nilai R 2 iaitu 0.9565 manakala penggumpal kimia kawalan, alum mempunyai nilai R 2 iaitu 0.7920. Ini membuktikan bahawa M. oleifera mempunyai potensi tinggi untuk penuaian mikroalga yang berkecekapan tinggi dan murah serta penyesuaian teknologi penuaian biologi terutamanya untuk tujuan makanan akuakultur di Malaysia.

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Harvesting of microalgae by flocculation with poly (γ-glutamic acid)

Cited by 191 publications

References 26 publications

A biorefinery for Nannochloropsis: Induction, harvesting, and extraction of EPA-rich oil and high-value protein

A biorefinery for Nannochloropsis: Induction, harvesting, and extraction of EPA-rich oil and high-value protein

Effect of voltage and electrode material on electroflocculation of Scenedesmus acuminatus

Moringa oleifera SEED DERIVATIVES AS POTENTIAL BIO-COAGULANT FOR MICROALGAE Chlorella Sp. HARVESTING

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