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Biochar is considered a promising biosorbent for harmful organic pollutants in aqueous media. However, only a limited number of biochars derived from industrial sludges have been utilized due to their problematic high ash content and heavy metal leaching. In this study, a highly effective biochar was prepared as a superabsorbent for ciprofloxacin (CIP) from chemical manufacturing plant sludge via K 2 CO 3 -activated pyrolysis, and its CIP removal behavior was evaluated. Unlike sewage sludge, chemical manufacturing plant sludge contains low SiO 2 , resulting in an ultra-pure carbon (95.4%) based biochar with almost negligible ash content. As the pyrolysis temperature increased from 400 to 800 °C, the ordered graphitic carbon structure transformed into an amorphous carbon phase, and most oxygen-containing groups disappeared. However, the pore size significantly decreased to ∼4.5 nm due to the corrosive carbon volatilization caused by K 2 CO 3 , resulting in an extremely large surface area of 2331.8 m 2 /g. Based on its large surface area and porous carbon structure, the activated biochar at 800 °C (CAB-800) exhibited an outstanding CIP adsorption capacity of 555.56 mg/g. The CIP adsorption isotherm, kinetic, and thermodynamic studies were systematically investigated. The CIP adsorption on CAB-800 was mainly attributed to π-π interactions and hydrogen bond formation, with electrostatic interactions partially contributing to the adsorption reaction. From pH 2 to 12, CAB-800 showed an excellent CIP adsorption capacity of over 316.7 mg/g, with adsorption favored under acidic conditions. Except for HCO 3 - and CO 3 2- , the presence of anions and humic acids did not significantly affect CIP adsorption capacity. These results demonstrate that biochar produced from chemical manufacturing industry sludge via K 2 CO 3 activation is a highly feasible material for the removal of CIP from aqueous media., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The growing interest in microalgae and cyanobacteria biomass as an alternative to traditional animal feed is hindered by high production costs. Using wastewater (WW) as a cultivation medium could offer a solution, but this approach risks introducing harmful substances into the biomass, leading to significant safety concerns. In this study, we addressed these challenges by selectively extracting nitrates and phosphates from WW using drinking water treatment residuals (DWTR) and chitosan. This method achieved peak adsorption capacities of 4.4 mg/g for nitrate and 6.1 mg/g for phosphate with a 2.5 wt% chitosan blend combined with DWTR-nitrogen. Subsequently, these extracted nutrients were employed to cultivate Spirulina platensis , yielding a biomass productivity rate of 0.15 g/L/d, which is comparable to rates achieved with commercial nutrients. By substituting commercial nutrients with nitrate and phosphate from WW, we can achieve a 18 % reduction in the culture medium cost. While the cultivated biomass was initially nitrogen-deficient due to low nitrate levels, it proved to be protein-rich, accounting for 50 % of its dry weight, and contained a high concentration of free amino acids (1260 mg/g), encompassing all essential amino acids. Both in vitro and in vivo toxicity tests affirmed the biomass's safety for use as an animal feed component. Future research should aim to enhance the economic feasibility of this alternative feed source by developing efficient adsorbents, utilizing cost-effective reagents, and implementing nutrient reuse strategies in spent mediums., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Objective: To analyze the outcomes of coil embolization (CE) for unruptured intracranial aneurysm (UIA) according to region and hospital size based on National Health Insurance Service data in South Korea., Methods: The incidence of complications, including intracranial hemorrhage (ICRH) and cerebral infarction (CI), occurring within 3 months and the 1-year mortality rates in UIA patients who underwent CE in 2018 were analyzed. Hospitals were classified as tertiary referral general hospitals (TRGHs), general hospitals (GHs) or semigeneral hospitals (sGHs) according to their size, and the administrative districts of South Korea were divided into 15 regions., Results: In 2018, 8425 (TRGHs, 4438; GHs, 3617; sGHs, 370) CEs were performed for UIAs. Complications occurred in 5.69% of patients seen at TRGHs, 13.48% at GHs, and 20.45% at sGHs. The complication rate in TRGHs was significantly lower than that in GHs (p=0.039) or sGHs (p=0.005), and that in GHs was significantly lower than that in sGHs (p=0.030). The mortality rates in TRGHs, GHs, and sGHs were 0.81%, 2.16%, and 3.92%, respectively, with no significant difference. Despite no significant difference in the mortality rates, the complication rate significantly increased as the number of CE procedures per hospital decreased (p=0.001; rho=-0.635). Among the hospitals where more than 30 CEs were performed for UIAs, the incidence of CIs (p=0.096, rho=-0.205) and the mortality rates (3 months, p=0.048, rho=-0.243; 1 year, p=0.009, rho=-0.315) significantly decreased as the number of CEs that were performed increased and no significant difference in the incidence of post-CE ICRH was observed., Conclusion: The complication rate in patients who underwent CE for UIA increased as the hospital size and physicians' experience in conducting CEs decreased. We recommend nationwide quality control policies CEs for UIAs.

This study reports the complete genome sequence of bisphenol A-degrading bacterium Sphingobium sp. strain A3, which was isolated from a contaminated soil sample from the site of a factory fire in South Korea. The genome consists of a 6.53-Mbp chromosome and eight plasmid contigs (532,947 bp), with 6,406 protein-coding sequences and a GC content of 63.82%., (Copyright © 2021 Jung et al.)

We report the complete genome sequence of Gordonia rubripertincta SD5, isolated from a soil-derived di-(2-ethylhexyl) phthalate-degrading enrichment culture. The final genome assembly consists of a 5.10-Mbp chromosome and a plasmid (159 kbp). A total of 4,814 coding sequences were predicted, including 4,741 protein-coding sequences., (Copyright © 2020 Han et al.)

This study investigated the feasibility of using photoheterotrophic microalga, Desmodesmus armatus SCK, for removal of cesium (Cs + ) followed by recovery process using magnetic nanoparticles. The comparison of three microalgae results indicated that D. armatus SCK removed the most Cs + at both 25 °C and 10 °C. The results also revealed that the use of microalga grown in potassium (K + )-starved condition improves the accumulation of Cs + . Heterotrophic mode with addition of volatile fatty acids (VFAs), especially acetic acids (HAc), also enhanced removal of Cs + by K + -starved D. armatus SCK; maximum removal efficiency of Cs + was almost 2-fold higher than that of cells grown without organic carbon source. The Cs + taken up by this microalga was efficiently harvested using magnetic nanoparticles, polydiallyldimethylammonium (PDDA)-FeO 3 . Finally, this strain eliminated more than 99% of radioactive 137 Cs from solutions of 10, 100, and 1000 Bq mL -1 . Therefore, use of K + -starved microalga, D. armatus SCK, with VFAs could be promising means to remove the Cs from the liquid wastes., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

In the present work, we report the complete genome sequence of Lactobacillus harbinensis NSMJ42, isolated from makgeolli (a Korean traditional alcoholic beverage) in South Korea. The final genome assembly consists of a 3.29-Mbp chromosome with 3,082 protein-coding sequences and a G+C content of 53.36%., (Copyright © 2019 Jung et al.)

Montmorillonite (MMT) is a highly promising material for use in drug delivery due to its high drug loading capacity and controlled drug release properties. MMT protects drug molecules between layered structure; however, drug release from MMT is sustained less than 6 h, which is insufficient for the release of antibiotics. This study sought to synthesize an antibiotic delivery material with more sustained release properties. A ciprofloxacin (CIP)-MMT composite was fabricated using carboxymethylated nanocellulose (CMCNF). A simple adsorption reaction intercalated 31.1% of CIP molecules present into the MMT under optimized conditions (pH 5, CIP = 1000 mg/L, Reaction time = 3 h). The synthesized CIP-MMT composite was fabricated using 1.5, 2, or 3 wt% CMCNF. Increasing the CMCNF content delayed the erosion of the CMCNF matrix and prevented rapid dissolution of the CIP-MMT composite. In vitro release experiments revealed that the CIP-MMT composite material provided the sustained release of CIP over 6 h. Erosion of the 3 wt% CMCNF-CIP-MMT composite occurred slowly and provided 48 h of sustained CIP release. An anti-bacterial test revealed that the 3 wt% CMCNF-CIP-MMT composite displayed the most constant antibacterial activity over 12 days. These results demonstrated that the CMCNF prepared with CIP intercalation in MMT was highly effective in prolonging the antibiotic release., (Copyright © 2019 Elsevier B.V. All rights reserved.)

We evaluated the potential sequestration of cesium (Cs + ) by microalgae under heterotrophic growth conditions in an attempt to ultimately develop a system for treatment of radioactive wastewater. Thus, we examined the effects of initial Cs + concentration (100-500 μM), pH (5-9), K + and Na + concentrations (0-20 mg/L), and different organic carbon sources (acetate, glycerol, glucose) on Cs + removal. Our initial comparison of nine microalgae indicated that Desmodesmus armatus SCK had removed the most Cs + under various environmental conditions. Addition of organic substrates significantly enhanced Cs + uptake by D. armatus, even in the presence of a competitive cation (K + ). We also applied magnetic nanoparticles coated with a cationic polymer (polyethylenimine) to separate 137 Cs-containing microalgal biomass under a magnetic field. Our technique of combining bioaccumulation and magnetic separation successfully removed more than 90% of the radioactive 137 Cs from an aqueous medium. These results clearly demonstrate that the method described here is a promising bioremediation technique for treatment of radioactive liquid waste.

Leuconostoc kimchii strain NKJ218 was isolated from homemade kimchi in South Korea. The whole genome was sequenced using the PacBio RS II and Illumina NovoSeq 6000 platforms. Here, we report a genome sequence of strain NKJ218, which consists of a 1.9-Mbp chromosome and three plasmid contigs. A total of 2,005 coding sequences (CDS) were predicted, including 1,881 protein-coding sequences., (Copyright © 2019 Jung et al.)

The successful production of microalgal biomass requires the precise coordination of many different steps. Cell harvesting is a central process in all methods currently used for the production of microalgal biomass. Therefore, improving the harvesting process itself, and using a harvesting method that is compatible with adjacent steps, is necessary to prevent problems that may occur during downstream processing. This study examined the potential of the cationic biopolymer ε-poly-L-lysine (ε-PLL) for use in the harvest of microalgae (Chlorella ellipsoidea). The effects of ε-PLL concentration and mixing intensity on flocculation efficiency and operating costs were determined. We found that ε-PLL was not toxic to microalgal cells at concentrations of up to 25 mg/L, based on the photosystem II quantum yield. A recovery rate of 95% was achieved using 19 mg/L ε-PLL, and the estimated harvest cost was 20 US$/ton of harvested biomass. Moreover, ε-PLL displayed antimicrobial properties, leaving the harvested biomass intact and pure. Therefore, the use of ε-PLL-induced flocculation appears to be an attractive option when harvesting microalgal biomass for use as low- and high-value commodities for humans or animals.

A Gram-positive, facultative anaerobic, catalase-negative, non-motile, non-spore-forming and rod-shaped lactic acid bacterium strain, denoted as NFFJ11 T and isolated from total mixed fermentation feed in the Republic of Korea, was characterized through polyphasic approaches, including sequence analyses of the 16S rRNA gene and housekeeping genes ( rpoA and pheS ), determination of average nucleotide identity and in silico DNA-DNA hybridization, fatty acid methyl ester analysis, and phenotypic characterization. Phylogenetic analyses based on 16S rRNA, rpoA and pheS gene sequences revealed that strain NFFJ11 T belonged to the genus Companilactobacillus . The 16S rRNA gene sequence of strain NFFJ11 T exhibited high similarity to Companilactobacillus formosensis S215 T (99.66 %), Companilactobacillus farciminis Rv4 na T (99.53 %), Companilactobacillus crustorum LMG 23699 T (99.19 %), Companilactobacillus futsaii YM 0097 T (99.06 %), Companilactobacillus zhachilii HBUAS52074 T (98.86 %) and Companilactobacillus heilongiiangensis S4-3 T (98.66 %). However, average nucleotide identity and in silico DNA-DNA hybridization values for these type strains were in the range of 79.90-92.93 % and 23.80-49.30 %, respectively, which offer evidence that strain NFFJ11 T belongs to a novel species of the genus Companilactobacillus . The cell-wall peptidoglycan type was A4α (l-Lys-d-Asp) and the G+C content of the genomic DNA was 35.7 mol%. The main fatty acids of strain NFFJ11 T were C 18 : 1  ω 9 c (43.3 %), C 16 : 0 (20.1 %) and summed feature 7 (18.3 %; comprising any combination of C 19 : 1  ω 7 c , C 19 : 1  ω 6 c and C 19 : 0 cyclo ω 10 c ). Through polyphasic taxonomic analysis, it was observed that strain NFFJ11 T represents a novel species belonging to the genus Companilactobacillus , for which the name Companilactobacillus pabuli sp. nov. is proposed. The type strain is NFFJ11 T (= KACC 21771 T = JCM 34088 T ).

The feasibility of a carbon recycling system that transforms algal residue to volatile fatty acids (VFAs) for re-cultivating microalgae was evaluated based on a carbon balance analysis of major VFAs consisting of acetate (HAc), propionate (HPr), and butyrate (HBu). This system largely involves two processes: (i) bioconversion of algal residue to VFAs by anaerobic fermentation, and (ii) cultivation of microalgae using the produced VFAs. The carbon balance for each unit process was examined to assess how much carbon in algal residue can be converted to these major VFAs and then assimilated to microalgae biomass. First, the yield and the profile of VFAs from raw algae (RA) and lipid-extracted algae (LEA) at psychrophilic (15 °C), mesophilic (35 °C), and thermophilic conditions (55 °C) were compared. When digesting the LEA under the thermophilic condition, the highest conversion yield, 0.36 (g carbon in VFAs/g carbon in biomass), with a compositional ratio of 6:1:3 (HAc: HPr: HBu) was obtained. Consumption of VFAs for microalgal growth reached a maximum value of 0.66 (g VFAs assimilated to biomass/g VFAs provided) at the compositional ratio of 6:1:3. Consequently, the maximum total carbon recycling ratio was 23.8% when fermenting LEA at the thermophilic condition. Our findings comprehensively revealed that establishing conditions that convert LEA to higher content of acetate is a decisive factor. It was estimated that around 40% of the total carbon from the LEA can be recovered for the production of algal biomass, when increasing the VFA conversion yield beyond 60% by adopting pretreatment methods., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Microalgae have been extensively studied for the production of various products. However, to date, microalgal biomass has not become economically feasible, mainly due to different issues such as contamination from various sources that occurs during downstream processes, and which leads to low quality biomass with limited application. In this study, to overcome contamination by flocculants and other microorganisms, the cationic biopolymer α-Poly-l-lysine (α-PLL) was applied. The cationic amine moiety and polymeric chain of α-PLL rendered microalgal harvesting efficient. With increasing α-PLL chain length, efficient dose- and time-dependent harvesting was achieved. In addition to efficient flocculation performance, biomass harvested using α-PLL showed suppressed biological contamination through the inherent antimicrobial activity of α-PLL. Thus, it is possible to upgrade the quality and storability of produced microalgal biomass using α-PLL-induced flocculation., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

This study examined the feasibility of using an algal-bacterial process for removal of phenol and NH 4 + -N from differently diluted coke wastewater with simultaneous production of biomass. Under illumination, microalgal-bacterial (MSB) cultures performed complete phenol degradation at all dilutions of coke wastewater while sole microalgal culture (MSA) degraded a maximum of 27.3% of phenol (initial concentration: 24.0mgL -1 ) from 5-fold diluted wastewater. Furthermore, the MSB culture had the highest rate of NH 4 + -N removal (8.3mgL -1 d -1 ) and fatty acid production (20mgL -1 d -1 ) which were 2.3- and 1.5-fold higher than those observed in the MSA cultures, probably due to decreases in toxic organic pollutants. Multivariate analyses indicated that co-cultivation of activated sludge was directly correlated with the elevated removals of phenol and NH 4 + -N. In the presence of sludge, adequate dilution of the coke wastewater can maximize the effect of bacteria on NH 4 + -N removal and biomass production., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Five technologies, coagulation, electro-flotation (EF), electro-coagulation-flotation (ECF), centrifugation, and membrane filtration, were systematically assessed for their adequacy of harvesting Aurantiochytrium sp. KRS101, a heterotrophic microalgal species that has much higher biomass concentration than photoautotrophic species. Coagulation, EF, and ECF were found to have limited efficiency. Centrifugation was overly powerful to susceptible cells like Aurantiochytrium sp. KRS101, inducing cell rupture and consequently biomass loss of over 13%. Membrane filtration, in particular equipped with an anti-fouling turbulence generator, turned out to be best suited: nearly 100% of harvesting efficiency and low water content in harvested biomass were achieved. With rotation rate increased, high permeate fluxes could be attained even with extremely concentrated biomass: e.g., 219.0 and 135.0 L/m(2)/h at 150.0 and 203.0 g/L, respectively. Dynamic filtration appears to be indeed a suitable means especially to obtain highly concentrated biomass that have no need of dewatering and can be directly processed., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Changes in algal and bacterial communities during thiocyanate (SCN(-)) decomposition in a microalga-mediated process were studied. Pyrosequencing indicated that Thiobacillus bacteria and Micractinium algae predominated during SCN(-) hydrolysis, even after its complete degradation. Principal components analysis and evenness profiles (based on the Pareto-Lorenz curve) suggested that the changes in the bacterial communities were driven by nitrogen and sulfur oxidation, pH changes, and photoautotrophic conditions. The populations of predominant microalgae remained relatively stable during SCN(-) hydrolysis, but the proportion of bacteria - especially nitrifying bacteria - fluctuated. Thus, the initial microalgal population may be crucial in determining which microorganisms dominate when the preferred nitrogen source becomes limited. The results also demonstrated that microalgae and SCN(-)-hydrolyzing bacteria can coexist, that microalgae can be effectively used with these bacteria to completely treat SCN(-), and that the structure of the algal-bacterial community is more stable than the community of nitrifying bacteria alone during SCN(-) degradation., (Copyright © 2015. Published by Elsevier Ltd.)

This work describes the development of a microalga-mediated process for simultaneous removal of residual ammonium nitrogen (NH4(+)-N) and production of lipids from biologically treated coke effluent. Four species of green algae were tested using a sequential mixotrophic process. In the first phase-CO2-supplied mixotrophic condition-all microalgae assimilated NH4(+)-N with no evident inhibition. In second phase-volatile fatty acids (VFAs)-supplied mixotrophic condition-removal rates of NH4(+)-N and biomass significantly increased. Among the microalgae used, Arctic Chlorella sp. ArM0029B had the highest rate of NH4(+)-N removal (0.97 mg/L/h) and fatty acid production (24.9 mg/L/d) which were 3.6- and 2.1-fold higher than those observed under the CO2-supplied mixotrophic condition. Redundancy analysis (RDA) indicated that acetate and butyrate were decisive factors for increasing NH4(+)-N removal and fatty acid production. These results demonstrate that microalgae can be used in a sequential process for treatment of residual nitrogen after initial treatment of activated sludge., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

There is an increasing interest in the use of cultivated microalgae to simultaneously produce biodiesel and remove nutrients from various wastewaters. For this purpose, Tetraselmis suecica was cultivated in flasks and fermenters using diluted food-waste recycling wastewater (FRW). The effect of FRW dilution on T. suecica growth and nutrient removal was initially tested in flasks. The maximal microalgal concentration after 14 days was in medium with a twofold dilution (28.3 × 10(6) cells/mL) and a fivefold dilution (25.5 × 10(6) cells/mL). When fivefold diluted medium was used in fermenters, the final dry cell weight of T. suecica was 2.0 g/L. The removal efficiencies of ammonium and phosphate in the fermenters were 99.0 and 52.3%, respectively. In comparison with the results of previous studies, the growth data of T. suecica in the FRW medium indicate that microalgal cultivation system incorporating removal of nutrients in FRW is feasible at the field level.

Advances in harvesting of microalgae are needed for the efficient and economical production of microalgal biodiesel. In addition to improvements in recovery efficiency, developments in harvest technology should focus on reducing the adverse impact of subsequent processes, and should also allow water recycling. We investigated a continuous electrochemical approach for microalgal biodiesel production. Instead of conventional DC, pulsed DC was applied as a method of polarity exchange and its performance was analyzed in terms of recovery efficiency, electricity consumption, and residual Al concentration. Under optimized pulsed-DC conditions, 32 % less electricity was required and 7 % less Al was remained after continuous harvesting and there was no decrease in recovery efficiency compared to the continuous harvesting by conventional DC. We also examined the effect of this new protocol on biodiesel quality and water reusability. There were no differences in the microalgal oil composition before and after electrolytic harvesting. In addition, the harvested oil quality, based on four key parameters, was superior to that produced by other terrestrial crops. Lastly, there was no retardation of growth in recycled medium relative to that in fresh medium.

In this work, a cooperative algal-bacterial system that efficiently degrades thiocyanate (SCN(-)), a toxic contaminant, and exhibits high lipid productivity, was developed. A consortium of mixed bacteria (activated sludge) and microalgae was sequentially cultivated under photoautotrophic and photoheterotrophic modes. The hydrolysis of SCN(-) to ammonium (NH4(+))-nitrogen and subsequent nitrification steps were performed by the initial activated sludge under lithoautotrophic conditions. The NH4(+) and oxidized forms of nitrogen, nitrite (NO2(-)) and nitrate (NO3(-)), were then assimilated and removed by the microalgal cells when light was supplied. After the degradation of SCN(-), the cultivation mode was changed to photoheterotrophic conditions in a sequential manner. Algal-bacterial cultures containing Chlorella protothecoides and Ettlia sp. yielded significantly increased lipid productivity under photoheterotrophic conditions compared to photoautotrophic conditions (28.7- and 17.3-fold higher, respectively). Statistical methodologies were also used to investigate the effects of volatile fatty acids and yeast extract on biomass and lipid production., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

In this work, a method for simultaneously degrading the toxic pollutant, thiocyanate, and producing microalgal lipids using mixed microbial communities was developed. Aerobic activated sludge was used as the seed culture and thiocyanate was used as the sole nitrogen source. Two cultivation methods were sequentially employed: a lithoautotrophic mode and a photoautotrophic mode. Thiocyanate hydrolysis and a nitrification was found to occur under the first (lithoautotrophic) condition, while the oxidized forms of nitrogen were assimilated by the photoautotrophic consortium and lipids were produced under the second condition. The final culture exhibited good settling efficiency (∼ 70% settling over 10 min), which can benefit downstream processing. The highest CO2 fixation rate and lipid productivity were observed with 2.5% and 5% CO2, respectively. The proposed integrated algal-bacterial system appears to be a feasible and even beneficial option for thiocyanate treatment and production of microbial lipids., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The biology of Aurantiochytrium sp. KRS101 was thoroughly investigated to enhance its production of biodiesel and docosahexaenoic acid (DHA). Nutrients and salinity were optimized to prevent biomass loss due to cell rupture. Calculation of yield coefficients showed that nitrogen was mostly responsible for the early stage of cell growth or division, whereas carbon was necessary for the entire process of cell development, particularly cell enlargement during late stages. Using these distinctive yield coefficients, a modified fed-batch cultivation method was designed, resulting in increases in palmitic acid (PA) and DHA production of up to 137% and 29%, respectively. This modified fed-batch cultivation method, using appropriate supplies of nitrogen and carbon, may improve the yields of PA and DHA, thus expanding the biotechnological applications of Aurantiochytrium sp. KRS101., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Waste spent yeast from brewery industry was used as a sole growth substrate to grow an oleaginous yeast Cryptococcus curvatus for the purpose of biodiesel production. Approximately 7 g/l/d of biomass productivity was obtained using only spent yeast (30 g/l) without additional nutrients and pretreatment of any kind. To make best use of available nutrients in the spent yeast, stepwise cultivation was carried out in a batch culture mode and the highest biomass and lipid content, which were 50.4 g/l and 37.7%, respectively, were obtained at 35:1 of C/N ratio. Lipid from C. curvatus was found to be a quality-sufficient source of oil as a transportation fuel in terms of cetane, iodine values, and oxidation stability, although the values of cold filter plugging point were less desirable. Economic evaluation revealed that the use of the spent yeast could significantly reduce the unit cost of yeast-based biodiesel production., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

A cultivation system in the two-stage photoautotrophic-photoheterotrophic/mixotrophic mode was adapted to maximize lipid productivity of two freshwater strains of Chlorella sp. grown in brewery wastewater (BWW). The endogenous Chlorella sp. isolated from BWW had a higher growth rate than wild-type Chlorella vulgaris (UTEX-265) while C. vulgaris (UTEX-265) had a higher maximal biomass and lipid contents than that of endogenous Chlorella sp., resulting in more than 90% of the inorganic nutrients in both total nitrogen (TN) and phosphorus (TP) was removed during the first stage in the two-stage photoautotrophic-photoheterotrophic mode in each Chlorella sp. The maximal biomass and lipid contents of C. vulgaris (UTEX-265) for single stage photoautotrophic cultivation were 1.5 g/L and 18%, respectively. Importantly, during two-stage photoautotrophic-photoheterotrophic cultivation for C. vulgaris (UTEX-265), the biomass was increased to 3.5 g/L, and the lipid productivity was increased from 31.1 to 108.0mg/L day., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

In the present study, spent yeast from a brewery was used as the growth substrate for the docosahexaenoic acid (DHA)-rich microalga, Aurantiochytrium sp. KRS101. A significant biomass yield (6.69 g/l/d) was obtained using only spent yeast as the growth substrate, with simple stirring as pretreatment. Maximization of nutrient utilization through the use of stepwise cultivation increased the yield to 31.8 g/l of biomass. DHA constituted 38.2% (w/w) of the total fatty acids, and the highest DHA productivity was observed when the C/N ratio was 20:1 (w/w). Spent yeast thus served as a good growth substrate for the production of DHA. Economic assessment revealed that stepwise cultivation using spent yeast as either the sole growth substrate or as a nutrient source could substantially reduce the production cost of microalgal DHA., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Microalgae have great potential as a feedstock for biofuel production. Continuous operation is an important benefit of the continuous electrolytic microalgae (CEM) harvest system, but it is necessary to optimize cultivability and recovery efficiency in order to improve overall performance. Two pairs of best-candidate electrodes for polarity exchange (PE) were examined to improve these two key factors: (i) aluminum and dimensionally stable anode (Al-DSA), and (ii) Al-platinum (Al-Pt). Al-DSA was better than Al-Pt because it led to less cell damage and was less expensive. Moreover, cell viability and recovery were improved by optimizing the timing of PE. A P1:P2 ratio of 1:1.5 at 5min and 1:1.2 at 10min yielded the best results, with greatly reduced electricity consumption and enhanced cell viability and recovery. The CEM harvest system appears to be a well-suited option for the harvest of microalgae for biofuel production., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

There is increasing interest in the use of microalgae as a renewable source for the production of fuels and chemicals, but improvements are needed in all steps of this process, including harvesting. A continuous microalgae harvest system was developed based on electrolysis, referred to here as a continuous electrolytic microalgae (CEM) harvest system. This innovative system combines cultivation and harvesting and enables continuous and efficient concentration of microalgae. The electrodes were subject to a polarity exchange (PE) in the middle of the operation to further improve the harvest efficiency. Use of PE, rather than conventional electro-coagulation-flotation (ECF), led to more efficient cell recovery and more uniform recovery over the entire harvest chamber. In addition, PE increased the cell growth rate and the circulated cells remained intact after harvesting., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Highly toxic oxyanions, such as hexavalent chromium (Cr(VI)), have caused adverse effects on human health. This study evaluated the feasibility of using cationic surfactant-modified activated carbon (AC) to remove Cr(VI). To modify activated carbon using a cationic surfactant, AC was mixed with a surfactant solution of 0.5 critical micelle concentration (CMC), at which concentration the surfactant molecules exist as mono-molecules. Adsorption kinetics and an isotherm model were used to study the adsorption characteristics of Cr(VI) onto MAC. The adsorption capacity of MAC for Cr(V) was enhanced compared to that of AC. MAC modified by hexadecyltrimethylammonium had a higher adsorption capacity for the removal of Cr(VI) than that modified by cetylpyridinium. The modification of AC by a cationic surfactant enhanced both its Cr(VI) adsorption rate and its Cr(VI) adsorption capacity. The breakthrough point of MAC for Cr(VI) was 100 times greater than for the raw AC. As a result, MAC is a promising adsorbent to treat Cr(VI) in an aqueous stream.

The feasibility of catholyte conditioning with the acidic solution and pre-treatment of soil with acidic solution was investigated with the electrokinetic remediation of Zn and Ni contaminated field soil. The extraction of Zn and Ni from soil increased with the decrease in pH of the extracting solution and nitric acid was very effective to extract Zn and Ni from the soil. Conventional electrokinetic treatment and acetate buffer circulation method were not effective to remove Zn and Ni from the soil. Pre-treatment of the soil with acidic solution enhanced the desorption of Zn and Ni and catholyte conditioning with this solution was effective in maintaining the overall soil pH within the electrokinetic cell. The catholyte conditioning and pre-treatment method enhanced the removal of Zn and Ni up to 41% and 40% after operation for 4 weeks. More than 96% of Zn and Ni removed by electrokinetic remediation were due to the electromigration. Catholyte conditioning and the pre-treatment method is effective in enhancing metal removal in electrokinetic remediation.

Feasibility of electrolyte conditioning with strong acidic or alkaline solution on electrokinetic remediation of arsenic-contaminated mine tailing was investigated in the laboratory. The mine tailing contained calcium oxide of more than 50%. At alkaline condition, arsenic was precipitated with calcium, and formed calcium arsenate which is very stable solid. Catholyte conditioning with strong acidic solution and anolyte conditioning with strong alkaline solution showed similar efficiency to remove arsenic. At 4mAcm(-2) of current density, the removal efficiency of arsenic was 62% after 28 days operation with catholyte conditioning with 0.1M nitric acid.

Methylation associated inactivation of RASSF1, a putative tumor suppressor identified at 3p21.3, has been frequently observed in several human malignancies, including lung and breast cancers. To explore the penetrance of RASSF1 in gastric carcinogenesis, we performed expression and mutation analyses of 3 isotypes of RASSF1 (A, B, and C) in 150 gastric specimens, including 15 carcinoma cell lines. RASSF1A and RASSF1B transcripts were not expressed in 60% (9 of 15) and 33% (5 of 15) of gastric carcinoma cell lines, respectively, whereas RASSF1C was detectable in all cell lines. Bisulfite DNA sequencing analysis revealed that the CpG island in the RASSF1A promoter is hypermethylated in all RASSF1A-nonexpressing cell lines. In addition, both RASSF1A and RASSF1B were re-expressed by treatment with the demethylating agent 5-aza-2'-deoxycytidine. Among 90 primary gastric adenocarcinomas examined, 41 (46%) and 19 (21%) expressed no or abnormally low levels of RASSF1A and RASSF1B, respectively, and 12 (13%) tumors showed no expression of both isoforms. Loss or abnormal down-regulation of RASSF1A correlated with tumor stage and grade but not with histological types of tumors. Methylation-specific PCR analysis demonstrated that 95% (39 of 41) of RASSF1A-nonexpressing primary tumors are methylated at the CpG sites in the promoter, whereas none of the adjacent noncancerous or normal tissues are methylated. No somatic mutations were detected in RASSF1 transcripts expressed in unmethylated tumors. However, 10 methylated tumors, including 4 cell lines, showed low genomic levels of RASSF1 and expressed no RASSF1A transcripts, suggesting that RASSF1A inactivation might be caused by both epigenetic and genetic mechanisms in a subset of gastric adenocarcinomas. In conclusion, our data indicate that epigenetic transcriptional silencing of RASSF1, especially RASSF1A isoform, is a frequent event in gastric tumorigenesis and might play an important role in the malignant progression of gastric adenocarcinomas.