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Application of acid mine drainage for coagulation/flocculation of microalgal biomass
Salama, El-Sayed,Kim, Jung Rae,Ji, Min-Kyu,Cho, Dong-Wan,Abou-Shanab, Reda A.I.,Kabra, Akhil N.,Jeon, Byong-Hun Elsevier 2015 Bioresource technology Vol.186 No.-
<P><B>Abstract</B></P> <P>A novel application of acid mine drainage (AMD) for biomass recovery of two morphologically different microalgae species with respect to AMD dosage, microalgal cell density and pH of medium was investigated. Optimal flocculation of <I>Scenedesmus obliquus</I> and <I>Chlorella vulgaris</I> occurred with 10% dosage of AMD at an initial pH 9 for both 0.5 and 1.0g/L cell density. The flocculation efficiency was 89% for <I>S</I>. <I>obliquus</I> and 93% for <I>C</I>. <I>vulgaris</I>. Zeta potential (ZP) was increased from −10.66 to 1.77 and −13.19 to 1.33 for <I>S</I>. <I>obliquus</I> and <I>C</I>. <I>vulgaris</I>, respectively. Scanning electron microscope with energy-dispersive X-ray of the microalgae floc confirmed the sweeping floc formation mechanism upon the addition of AMD. Application of AMD for the recovery of microalgae biomass is a cost-effective method, which might further allow reuse of flocculated medium for algal cultivation, thereby contributing to the economic production of biofuel from microalgal biomass.</P> <P><B>Highlights</B></P> <P> <UL> <LI> AMD contains high amount of Fe(II)/Al(III) ions which are natural flocculants. </LI> <LI> Sweeping microalgal floc formation was the dominant mechanism in this study. </LI> <LI> AMD can be an efficient coagulant/flocculant for low-cost microalgae harvesting. </LI> </UL> </P>
Xiong, Jiu-Qiang,Kim, Sun-Joon,Kurade, Mayur B.,Govindwar, Sanjay,Abou-Shanab, Reda A.I.,Kim, Jung-Rae,Roh, Hyun-Seog,Khan, Moonis Ali,Jeon, Byong-Hun Elsevier 2019 Journal of hazardous materials Vol.370 No.-
<P><B>Abstract</B></P> <P>This study investigated the environmental effects of two common emerging contaminants, sulfamethazine (SMZ) and sulfamethoxazole (SMX), and their mixture using a green microalga, <I>Scenedesmus obliquus</I>. The calculated EC<SUB>50</SUB> values of SMZ, SMX, and their mixture (11:1 wt/wt) after 96 h were 1.23, 0.12, and 0.89 mg L<SUP>-1</SUP>, respectively. The toxicity of the mixture could be better predicted using a concentration addition model than an independent action model. The risk quotients of SMZ, SMX, and their mixture were >1 during the experiment, indicating their high potential risks on aquatic microorganisms. Despite their toxicity, <I>S. obliquus</I> exhibited 17.3% and 29.3% removal of 0.1 mg L<SUP>-1</SUP> and 0.2 mg L<SUP>-1</SUP> after 11 days of cultivation. The changes of SMZ and SMX removal were observed when combined, which showed a significantly improved removal of SMZ (up to 3.4 folds) with addition of SMX (0.2 mg L<SUP>-1</SUP>). The metabolic pathways of SMZ and SMX were proposed according to mass spectroscopic analysis, which showed six metabolites of SMX and seven intermediates of SMZ, formed as a result of ring cleavage, hydroxylation, methylation, nitrosation, and deamination.</P> <P><B>Highlights</B></P> <P> <UL> <LI> <I>Scenedesmus obliquus</I> was tolerant to SMZ, SMX, and their mixture, and could withstand their high doses. </LI> <LI> 96 h EC<SUB>50</SUB> of SMZ, SMX, and their mixture for <I>S. obliquus</I> was 1.23, 0.12, and 0.89 mg L<SUP>-1</SUP>. </LI> <LI> The risk quotients of SMZ, SMX, and their mixture were >1. </LI> <LI> The removal of SMZ and SMX was more in the mixture than their individual medium. </LI> <LI> Metabolic pathways of SMZ and SMX by <I>S. obliquus</I> were proposed. </LI> </UL> </P>
Abou-Shanab, Reda A.I.,El-Dalatony, Marwa M.,EL-Sheekh, Mostafa M.,Ji, Min-Kyu,Salama, El-Sayed,Kabra, Akhil N.,Jeon, Byong-Hun 한국생물공학회 2014 Biotechnology and Bioprocess Engineering Vol.19 No.3
Coupling of advanced wastewater treatment with microalgae cultivation for low-cost lipid production was demonstrated in this study. The microalgal species Micractinium reisseri and Scenedesmus obliquus were isolated from municipal wastewater mixed with agricultural drainage. M. reisseri was selected based on the growth rate and cultivated in municipal wastewater (influent, secondary and tertiary effluents) which varied in nutrient concentration. M. reisseri showed an optimal specific growth rate (${\mu}_opt$) of 1.15, 1.04, and 1.01 1/day for the influent and the secondary and tertiary effluents, respectively. Secondary effluent supported the highest phosphorus removal (94%) and saturated fatty acid content (40%). The highest lipid content (40%), unsaturated fatty acid content, including monounsaturated and polyunsaturated fatty acids (66%), and nitrogen removal (80%) were observed for tertiary effluent. Fatty acids accumulating in the microalgal biomass (M. reisseri) were mainly composed of palmitic acid, oleic acid, linoleic acid, and ${\alpha}$-linolenic acid. Cultivation of M. reisseri using municipal wastewater served a dual function of nutrient removal and biofuel feedstock generation.
Choi, Jeong-A,Hwang, Jae-Hoon,Dempsey, Brian A.,Abou-Shanab, Reda A. I.,Min, Booki,Song, Hocheol,Lee, Dae Sung,Kim, Jung Rae,Cho, Yunchul,Hong, Seungkwan,Jeon, Byong-Hun Royal Society of Chemistry 2011 ENERGY AND ENVIRONMENTAL SCIENCE Vol.4 No.9
<P>The influence of ultrasonication pretreatment on fermentative bioenergy [ethanol/hydrogen (H<SUB>2</SUB>)] production from a newly isolated microalgae biomass (<I>Scenedesmus obliquus</I> YSW15) was investigated. <I>S. obliquus</I> YSW15 biomass was sonicated for 0 min (control), 5 min (short-term treatment), 15 and 60 min (long-term treatment), which caused different states of cell lysis for microbial fermentation. Long-term sonication significantly damaged the microalgal cell integrity, which subsequently enhanced the bioenergy production. The accumulative bioenergy (ethanol/hydrogen) production after long-term sonication was almost 7 times higher than that after short-term treatment or the control. The optimal ratio of microalgal biomass to anaerobic inoculum for higher bioenergy production was 1 : 1. Microscopic analyses with an energy-filtering transmission electron microscope (EF-TEM) and an atomic force microscope (AFM) collectively indicated that cells were significantly damaged during sonication and that the carbohydrates diffused out of the microalgae interiors and accumulated on the microalgae surfaces and/or within the periplasm, which led to enhanced bioaccessibility and bioavailability of the biomass. These results demonstrate that ultrasonication is an effective pretreatment method for enhancing the fermentative bioenergy production from microalgal biomass.</P> <P>Graphic Abstract</P><P>Disintegration of algae cell structures during sonication released more algal cell wall carbohydrates to aqueous media, thereby exposing a larger surface area to fermentative microorganisms. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c1ee01068a'> </P>
Biological Conversion of Amino Acids to Higher Alcohols
El-Dalatony, Marwa M.,Saha, Shouvik,Govindwar, Sanjay P.,Abou-Shanab, Reda A.I.,Jeon, Byong-Hun Elsevier 2019 Trends in biotechnology Vol.37 No.8
<P>‘Higher’ alcohols, which contain more than two carbons, have a higher boiling point, higher cetane number, and higher energy density than ethanol. Blends of biodiesel and higher alcohols can be used in internal combustion engines as next-generation biofuels without any modification and are minimally corrosive over extensive use. Producing higher alcohols from biomass involves fermenting and metabolizing amino acids. In this review, we describe the pathways and regulatory mechanisms involved in amino acid bioprocessing to produce higher alcohols and the effects of amino acid supplementation as a nitrogen source for higher alcohol production. We also discuss the most recent approaches to improve higher alcohol production via genetic engineering technologies for three microorganisms: <I>Saccharomyces cerevisiae</I>, <I>Clostridium</I> spp., and <I>Escherichia coli</I>.</P> <P><B>Highlights</B></P> <P>Proteins are polymers of various amino acids, connected via peptide bonds and classified as a major feedstock for bioenergy production. Higher alcohols are high-density alternative fuels that increase the longevity of transportation fuels.</P> <P>Proteins have a significant role in the fermentation process by providing amino acids for the growth of microorganisms, and enhancement of sugar permeability, in carbohydrate-rich sources.</P> <P>Due to the environmental and economic advantages of recombinant DNA technology, fermentation is the most used process for industrial-scale alcohol production. Applying this technology to higher alcohols can significantly improve industrialization for advanced fuel production.</P> <P>Extraction techniques are used to separate and mitigate the toxicity of alcohols produced in the fermentation broth to maintain the microbial cell viability for longer.</P>
안용태,전병훈,김현철,조동완,Reda A.I. Abou-Shanab 한국자원공학회 2012 Geosystem engineering Vol.15 No.1
Zero-valent iron (ZVI) treatment system combined with pH adjustment, aeration, sedimentation, and microfiltration processes was developed for the robust removal of nitrate from groundwater. Powdered ZVI dosed at 10 g L-1 removed nitrate by 166 mg L-1, of which 80% were converted to ammonium ion for a given contact time of 125 hr. By diffusing gaseous carbon dioxide (CO2)into the ZVI reactor, pH was desirably controlled in the range of 5.5-6.5, and concurrently <0.5 mg L-1 dissolved oxygen was consistently maintained during the longer-term of dissolved oxygen ZVI treatment system. The combination of ZVI treatment and CO2 gas bubbling reached up to 35% removal of nitrate and passivation on the surface of ZVI was prevented by diffusing CO2 gas. Soluble Fe (II) concentration of mixed liquor in the ZVI reactor ranged between 0.2 and 7.8 mg L-1, and Fe (II) dissolved in the ZVI treated water was almost completely removed by subsequent aeration. The overall result shows that the novel ZVI treatment system is significantly promising to remove nitrate in groundwater and therefore to meet the regulatory limit for drinking water.
Ji, Min-Kyu,Kim, Hyun-Chul,Sapireddy, Veer Raghavulu,Yun, Hyun-Shik,Abou-Shanab, Reda A I,Choi, Jaeyoung,Lee, Wontae,Timmes, Thomas C,Inamuddin,Jeon, Byong-Hun Springer International 2013 Applied microbiology and biotechnology Vol.97 No.6
<P>The feasibility of using a microalga Chlorella vulgaris YSW-04 was investigated for removal of nutrients from piggery wastewater effluent. The consequent lipid production by the microalga was also identified and quantitatively determined. The wastewater effluent was diluted to different concentrations ranging from 20 to 80 % of the original using either synthetic media or distilled water. The dilution effect on both lipid production and nutrient removal was evaluated, and growth rate of C. vulgaris was also monitored. Dilution of the wastewater effluent improved microalgal growth, lipid productivity, and nutrient removal. The growth rate of C. vulgaris was increased with decreased concentration of piggery wastewater in the culture media regardless of the diluent type. Lipid production was relatively higher when using synthetic media than using distilled water for dilution of wastewater. The composition of fatty acids accumulated in microalgal biomass was dependent upon both dilution ratio and diluent type. The microalga grown on a 20 % concentration of wastewater effluent diluted with distilled water was more promising for generating high-efficient biodiesel compared to the other culture conditions. The highest removal of inorganic nutrients was also achieved at the same dilution condition. Our results revealed the optimal pretreatment condition for the biodegradation of piggery wastewater with microalgae for subsequent production of high-efficient biodiesel.</P>