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Special Issue "Microalgal Biotechnology"

A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Green Chemistry".

Deadline for manuscript submissions: closed (30 June 2015).

Special Issue Editors

Guest Editor
Prof. Dr. Christopher Q. Lan

Department of Chemical and Biological Engineering, University of Ottawa, Canada
Website | E-Mail
Interests: Microalgal Biotechnology, Biofuels, Recombinant Protein Expression and Purification, Membrane Technologies, Personal Cooling
Guest Editor
Prof. Dr. Yanqun Li

College of Food Science and Technology, Guangdong Ocean University, East Huguangyan, Zhanjiang, 524088, Guangdong Province, China
E-Mail
Phone: 86-759-2396046
Interests: Microalgal Biotechnology, Food Science

Special Issue Information

Dear Colleagues,

Microalgae have been well established as promising cellular photobioreactors for biofuel production, CO2 sequestration, wastewater treatment, air pollution mitigation, phytoremediation of eutrophic waters, and production of platform and novel chemicals.  Nevertheless, tremendous challenges have been impeding commercial application of microalgae in many different ways and there are no simple solutions. This special issue invites contributions in the form of original research papers or review papers on all aspects of microalgal biotechnology, dedicated to both the understanding of the fundamentals and development of industry-oriented technologies.  Some of these topics are as follows:

 

  1. Gene engineering of microalgae;
  2. Development of microalgal strains using natural selection, mutagenesis, or genetic engineering;
  3. Development and optimization of media and processes for microalgal farming;
  4. Heat transfer, mass transfer, light capturing and distribution in photobioreactors;
  5. Design and operation of microagal farming systems at small, pilot and large scale;
  6. Kinetics of growth and product formation of microalgae;
  7. Effects of environmental factors on microalgae;
  8. Contaminations and control of biological agents in microalgal farms;
  9. Production of platform or novel chemicals from microalgae;
  10. Microalgae for CO2 mitigation, wastewater treatment, phytoremediation, air pollution mitigation;
  11. Microalgae as feedstock for biofuels, animinal feeds, and human foods.

 

Prof. Dr. Christopher Q. Lan
Prof. Dr. Yanqun Li
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. International Journal of Molecular Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.


Keywords

  • microalgae
  • sustainability
  • co2 mitigation
  • renewable energy

Published Papers (10 papers)

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Research

Jump to: Review

Open AccessArticle
The Use of the Schizonticidal Agent Quinine Sulfate to Prevent Pond Crashes for Algal-Biofuel Production
Int. J. Mol. Sci. 2015, 16(11), 27450-27456; https://doi.org/10.3390/ijms161126035
Received: 27 August 2015 / Revised: 4 November 2015 / Accepted: 9 November 2015 / Published: 17 November 2015
Cited by 8 | PDF Full-text (1127 KB) | HTML Full-text | XML Full-text
Abstract
Algal biofuels are investigated as a promising alternative to petroleum fuel sources to satisfy transportation demand. Despite the high growth rate of algae, predation by rotifers, ciliates, golden algae, and other predators will cause an algae in open ponds to crash. In this [...] Read more.
Algal biofuels are investigated as a promising alternative to petroleum fuel sources to satisfy transportation demand. Despite the high growth rate of algae, predation by rotifers, ciliates, golden algae, and other predators will cause an algae in open ponds to crash. In this study, Chlorella kessleri was used as a model alga and the freshwater rotifer, Brachionus calyciflorus, as a model predator. The goal of this study was to test the selective toxicity of the chemical, quinine sulfate (QS), on both the alga and the rotifer in order to fully inhibit the rotifer while minimizing its impact on algal growth. The QS LC50 for B. calyciflorus was 17 µM while C. kessleri growth was not inhibited at concentrations <25 µM. In co-culture, complete inhibition of rotifers was observed when the QS concentration was 7.7 µM, while algal growth was not affected. QS applications to produce 1 million gallons of biodiesel in one year are estimated to be $0.04/gallon or ~1% of Bioenergy Technologies Office’s (BETO) projected cost of $5/gge (gallon gasoline equivalent). This provides algae farmers an important tool to manage grazing predators in algae mass cultures and avoid pond crashes. Full article
(This article belongs to the Special Issue Microalgal Biotechnology)
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Open AccessArticle
Novel Electrokinetic Microfluidic Detector for Evaluating Effectiveness of Microalgae Disinfection in Ship Ballast Water
Int. J. Mol. Sci. 2015, 16(10), 25560-25575; https://doi.org/10.3390/ijms161025560
Received: 25 June 2015 / Revised: 13 August 2015 / Accepted: 13 October 2015 / Published: 26 October 2015
Cited by 9 | PDF Full-text (1607 KB) | HTML Full-text | XML Full-text
Abstract
Ship ballast water treatment methods face many technical challenges. The effectiveness of every treatment method usually is evaluated by using large scale equipment and a large volume of samples, which involves time-consuming, laborious, and complex operations. This paper reports the development of a [...] Read more.
Ship ballast water treatment methods face many technical challenges. The effectiveness of every treatment method usually is evaluated by using large scale equipment and a large volume of samples, which involves time-consuming, laborious, and complex operations. This paper reports the development of a novel, simple and fast platform of methodology in evaluating the efficiency and the best parameters for ballast water treatment systems, particularly in chemical disinfection. In this study, a microfluidic chip with six sample wells and a waste well was designed, where sample transportation was controlled by electrokinetic flow. The performance of this microfluidic platform was evaluated by detecting the disinfection of Dunaliella salina (D. salina) algae in ballast water treated by sodium hypochlorite (NaClO) solution. Light-induced chlorophyll fluorescence (LICF) intensity was used to determine the viability of microalgae cells in the system, which can be operated automatically with the dimension of the detector as small as 50 mm × 24 mm × 5 mm. The 40 µL volume of sample solution was used for each treatment condition test and the validity of detection can be accomplished within about five min. The results show that the viability of microalgae cells under different treatment conditions can be determined accurately and further optimal treatment conditions including concentrations of NaClO and treatment time can also be obtained. These results can provide accurate evaluation and optimal parameters for ballast water treatment methods. Full article
(This article belongs to the Special Issue Microalgal Biotechnology)
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Open AccessArticle
Use of Copper to Selectively Inhibit Brachionus calyciflorus (Predator) Growth in Chlorella kessleri (Prey) Mass Cultures for Algae Biodiesel Production
Int. J. Mol. Sci. 2015, 16(9), 20674-20684; https://doi.org/10.3390/ijms160920674
Received: 2 July 2015 / Revised: 17 August 2015 / Accepted: 18 August 2015 / Published: 31 August 2015
Cited by 11 | PDF Full-text (1328 KB) | HTML Full-text | XML Full-text
Abstract
A single Brachionus rotifer can consume thousands of algae cells per hour causing an algae pond to crash within days of infection. Thus, there is a great need to reduce rotifers in order for algal biofuel production to become reality. Copper can selectively [...] Read more.
A single Brachionus rotifer can consume thousands of algae cells per hour causing an algae pond to crash within days of infection. Thus, there is a great need to reduce rotifers in order for algal biofuel production to become reality. Copper can selectively inhibit rotifers in algae ponds, thereby protecting the algae crop. Differential toxicity tests were conducted to compare the copper sensitivity of a model rotifer—B. calyciflorus and an alga, C. kessleri. The rotifer LC50 was <0.1 ppm while the alga was not affected up to 5 ppm Cu(II). The low pH of the rotifer stomach may make it more sensitive to copper. However, when these cultures were combined, a copper concentration of 1.5 ppm was needed to inhibit the rotifer as the alga bound the copper, decreasing its bioavailability. Copper (X ppm) had no effect on downstream fatty acid methyl ester extraction. Full article
(This article belongs to the Special Issue Microalgal Biotechnology)
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Open AccessArticle
Assessing Transformations of Algal Organic Matter in the Long-Term: Impacts of Humification-Like Processes
Int. J. Mol. Sci. 2015, 16(8), 18096-18110; https://doi.org/10.3390/ijms160818096
Received: 29 May 2015 / Revised: 20 July 2015 / Accepted: 27 July 2015 / Published: 5 August 2015
Cited by 5 | PDF Full-text (3445 KB) | HTML Full-text | XML Full-text
Abstract
Algae and cyanobacteria are important contributors to the natural organic matter (NOM) of eutrophic water resources. The objective of this work is to increase knowledge on the modifications of algal organic matter (AOM) properties in the long term to anticipate blooms footprint in [...] Read more.
Algae and cyanobacteria are important contributors to the natural organic matter (NOM) of eutrophic water resources. The objective of this work is to increase knowledge on the modifications of algal organic matter (AOM) properties in the long term to anticipate blooms footprint in such aquatic environments. The production of AOM from an alga (Euglena gracilis) and a cyanobacteria (Microcystis aeruginosa) was followed up and characterized during the stationary phase and after one year and four months of cultivation, in batch experiments. Specific UV absorbance (SUVA) index, organic matter fractionation according to hydrophobicity and apparent molecular weight were combined to assess the evolution of AOM. A comparison between humic substances (HS) mainly derived from allochthonous origins and AOM characteristics was performed to hypothesize impacts of AOM transformation processes on the water quality of eutrophic water resources. Each AOM fraction underwent a specific evolution pattern, depending on its composition. Impacts of humification-like processes were predominant over release of biopolymers due to cells decay and led to an increase in the hydrophobic compounds part and molecular weights over time. However, the hydrophilic fraction remained the major fraction whatever the growth stage. Organic compounds generated by maturation of these precursors corresponded to large and aliphatic structures. Full article
(This article belongs to the Special Issue Microalgal Biotechnology)
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Open AccessArticle
A New Treatment Strategy for Inactivating Algae in Ballast Water Based on Multi-Trial Injections of Chlorine
Int. J. Mol. Sci. 2015, 16(6), 13158-13171; https://doi.org/10.3390/ijms160613158
Received: 2 March 2015 / Revised: 27 May 2015 / Accepted: 1 June 2015 / Published: 9 June 2015
Cited by 7 | PDF Full-text (858 KB) | HTML Full-text | XML Full-text
Abstract
Ships’ ballast water can carry aquatic organisms into foreign ecosystems. In our previous studies, a concept using ion exchange membrane electrolysis to treat ballast water has been proven. In addition to other substantial approaches, a new strategy for inactivating algae is proposed based [...] Read more.
Ships’ ballast water can carry aquatic organisms into foreign ecosystems. In our previous studies, a concept using ion exchange membrane electrolysis to treat ballast water has been proven. In addition to other substantial approaches, a new strategy for inactivating algae is proposed based on the developed ballast water treatment system. In the new strategy, the means of multi-trial injection with small doses of electrolytic products is applied for inactivating algae. To demonstrate the performance of the new strategy, contrast experiments between new strategies and routine processes were conducted. Four algae species including Chlorella vulgaris, Platymonas subcordiformis, Prorocentrum micans and Karenia mikimotoi were chosen as samples. The different experimental parameters are studied including the injection times and doses of electrolytic products. Compared with the conventional one trial injection method, mortality rate time (MRT) and available chlorine concentration can be saved up to about 84% and 40%, respectively, under the application of the new strategy. The proposed new approach has great potential in practical ballast water treatment. Furthermore, the strategy is also helpful for deep insight of mechanism of algal tolerance. Full article
(This article belongs to the Special Issue Microalgal Biotechnology)
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Open AccessArticle
Periodic CO2 Dosing Strategy for Dunaliella salina Batch Culture
Int. J. Mol. Sci. 2015, 16(5), 11509-11521; https://doi.org/10.3390/ijms160511509
Received: 20 March 2015 / Revised: 4 May 2015 / Accepted: 7 May 2015 / Published: 19 May 2015
Cited by 3 | PDF Full-text (927 KB) | HTML Full-text | XML Full-text
Abstract
A periodic CO2 dosing strategy for D. salina 19/30 batch culture is proposed. A model of periodic CO2 dosing including dosing time calculation, dosing interval estimation and final chlorophyll yield prediction was established. In experiments, 5% CO2/95% N2 [...] Read more.
A periodic CO2 dosing strategy for D. salina 19/30 batch culture is proposed. A model of periodic CO2 dosing including dosing time calculation, dosing interval estimation and final chlorophyll yield prediction was established. In experiments, 5% CO2/95% N2 gas was periodically dosed into D. salina culture. Two different gas dosing flow rates were tested. The corresponding dosing time for each flow rate was estimated via the model (10 min·d−1 for 0.7 L·min−1 and 36 min·d−1 for 0.3 L·min−1). Daily pH measurements showed that the pH of these cultures dosed periodically was always kept between 7.5 and 9.5, which highlights that periodic gas supply can maintain a suitable range of pH for microalgal growth without expensive buffers. Notably the culture dosed for set daily intervals was seen to have similar growth to the culture supplied constantly, but with much higher CO2 capture efficiency (11%–18%) compared to continuous dosing (0.25%). It shows great potential for using periodic gas supply to reduce cost, wasted gas and energy use. Full article
(This article belongs to the Special Issue Microalgal Biotechnology)
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Open AccessArticle
Mutation Breeding of Extracellular Polysaccharide-Producing Microalga Crypthecodinium cohnii by a Novel Mutagenesis with Atmospheric and Room Temperature Plasma
Int. J. Mol. Sci. 2015, 16(4), 8201-8212; https://doi.org/10.3390/ijms16048201
Received: 9 March 2015 / Revised: 1 April 2015 / Accepted: 7 April 2015 / Published: 13 April 2015
Cited by 11 | PDF Full-text (757 KB) | HTML Full-text | XML Full-text
Abstract
Extracellular polysaccharides (EPS) produced by marine microalgae have the potential to be used as antioxidants, antiviral agents, immunomodulators, and anti-inflammatory agents. Although the marine microalga Crypthecodinium cohnii releases EPS during the process of docosahexaenoic acid (DHA) production, the yield of EPS remains relatively [...] Read more.
Extracellular polysaccharides (EPS) produced by marine microalgae have the potential to be used as antioxidants, antiviral agents, immunomodulators, and anti-inflammatory agents. Although the marine microalga Crypthecodinium cohnii releases EPS during the process of docosahexaenoic acid (DHA) production, the yield of EPS remains relatively low. To improve the EPS production, a novel mutagenesis of C. cohnii was conducted by atmospheric and room temperature plasma (ARTP). Of the 12 mutants obtained, 10 mutants exhibited significantly enhanced EPS yield on biomass as compared with the wild type strain. Among them, mutant M7 was the best as it could produce an EPS volumetric yield of 1.02 g/L, EPS yield on biomass of 0.39 g/g and EPS yield on glucose of 94 mg/g, which were 33.85%, 85.35% and 57.17% higher than that of the wild type strain, respectively. Results of the present study indicated that mutagenesis of the marine microalga C. cohnii by ARTP was highly effective leading to the high-yield production of EPS. Full article
(This article belongs to the Special Issue Microalgal Biotechnology)
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Open AccessArticle
Combined Enzymatic and Mechanical Cell Disruption and Lipid Extraction of Green Alga Neochloris oleoabundans
Int. J. Mol. Sci. 2015, 16(4), 7707-7722; https://doi.org/10.3390/ijms16047707
Received: 27 February 2015 / Revised: 17 March 2015 / Accepted: 27 March 2015 / Published: 7 April 2015
Cited by 32 | PDF Full-text (3416 KB) | HTML Full-text | XML Full-text
Abstract
Microalgal biodiesel is one of the most promising renewable fuels. The wet technique for lipids extraction has advantages over the dry method, such as energy-saving and shorter procedure. The cell disruption is a key factor in wet oil extraction to facilitate the intracellular [...] Read more.
Microalgal biodiesel is one of the most promising renewable fuels. The wet technique for lipids extraction has advantages over the dry method, such as energy-saving and shorter procedure. The cell disruption is a key factor in wet oil extraction to facilitate the intracellular oil release. Ultrasonication, high-pressure homogenization, enzymatic hydrolysis and the combination of enzymatic hydrolysis with high-pressure homogenization and ultrasonication were employed in this study to disrupt the cells of the microalga Neochloris oleoabundans. The cell disruption degree was investigated. The cell morphology before and after disruption was assessed with scanning and transmission electron microscopy. The energy requirements and the operation cost for wet cell disruption were also estimated. The highest disruption degree, up to 95.41%, assessed by accounting method was achieved by the combination of enzymatic hydrolysis and high-pressure homogenization. A lipid recovery of 92.6% was also obtained by the combined process. The combined process was found to be more efficient and economical compared with the individual process. Full article
(This article belongs to the Special Issue Microalgal Biotechnology)
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Open AccessArticle
Rapid Characterization of Fatty Acids in Oleaginous Microalgae by Near-Infrared Spectroscopy
Int. J. Mol. Sci. 2015, 16(4), 7045-7056; https://doi.org/10.3390/ijms16047045
Received: 3 February 2015 / Revised: 9 March 2015 / Accepted: 19 March 2015 / Published: 27 March 2015
Cited by 6 | PDF Full-text (727 KB) | HTML Full-text | XML Full-text
Abstract
The key properties of microalgal biodiesel are largely determined by the composition of its fatty acid methyl esters (FAMEs). The gas chromatography (GC) based techniques for fatty acid analysis involve energy-intensive and time-consuming procedures and thus are less suitable for high-throughput screening applications. [...] Read more.
The key properties of microalgal biodiesel are largely determined by the composition of its fatty acid methyl esters (FAMEs). The gas chromatography (GC) based techniques for fatty acid analysis involve energy-intensive and time-consuming procedures and thus are less suitable for high-throughput screening applications. In the present study, a novel quantification method for microalgal fatty acids was established based on the near-infrared spectroscopy (NIRS) technique. The lyophilized cells of oleaginous Chlorella containing different contents of lipids were scanned by NIRS and their fatty acid profiles were determined by GC-MS. NIRS models were developed based on the chemometric correlation of the near-infrared spectra with fatty acid profiles in algal biomass. The optimized NIRS models showed excellent performances for predicting the contents of total fatty acids, C16:0, C18:0, C18:1 and C18:3, with the coefficient of determination (R2) being 0.998, 0.997, 0.989, 0.991 and 0.997, respectively. Taken together, the NIRS method established here bypasses the procedures of cell disruption, oil extraction and transesterification, is rapid, reliable, and of great potential for high-throughput applications, and will facilitate the screening of microalgal mutants and optimization of their growth conditions for biodiesel production. Full article
(This article belongs to the Special Issue Microalgal Biotechnology)
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Review

Jump to: Research

Open AccessReview
Effect of Metals, Metalloids and Metallic Nanoparticles on Microalgae Growth and Industrial Product Biosynthesis: A Review
Int. J. Mol. Sci. 2015, 16(10), 23929-23969; https://doi.org/10.3390/ijms161023929
Received: 18 August 2015 / Revised: 11 September 2015 / Accepted: 24 September 2015 / Published: 9 October 2015
Cited by 49 | PDF Full-text (848 KB) | HTML Full-text | XML Full-text
Abstract
Microalgae are a source of numerous compounds that can be used in many branches of industry. Synthesis of such compounds in microalgal cells can be amplified under stress conditions. Exposure to various metals can be one of methods applied to induce cell stress [...] Read more.
Microalgae are a source of numerous compounds that can be used in many branches of industry. Synthesis of such compounds in microalgal cells can be amplified under stress conditions. Exposure to various metals can be one of methods applied to induce cell stress and synthesis of target products in microalgae cultures. In this review, the potential of producing diverse biocompounds (pigments, lipids, exopolymers, peptides, phytohormones, arsenoorganics, nanoparticles) from microalgae cultures upon exposure to various metals, is evaluated. Additionally, different methods to alter microalgae response towards metals and metal stress are described. Finally, possibilities to sustain high growth rates and productivity of microalgal cultures in the presence of metals are discussed. Full article
(This article belongs to the Special Issue Microalgal Biotechnology)
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Int. J. Mol. Sci. EISSN 1422-0067 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
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