Chlorella Vulgaris ESP-31 Research Articles

Bioethanol production from Chlorella vulgaris ESP-31 grown in unsterilized swine wastewater

The potential of microalgae to remove nutrients from swine wastewater and accumulate carbohydrates was examined. Chlorella sorokiniana AK-1 and Chlorella vulgaris ESP-31 were grown in 10% unsterilized swine wastewater and obtained a maximum carbohydrate content and productivity of 42.5% and 189 mg L−1d−1, respectively. At 25% wastewater and 25% BG-11 concentration, the maximum carbohydrate productivity and total nitrogen removal efficiency of C. vulgaris ESP-31 were improved to 266 mg L−1d−1 and 54.2%, respectively. Further modifications in light intensity, inoculum size, and harvesting period enhanced the biomass growth, carbohydrate concentration, and total nitrogen assimilation to 3.6 gL−1, 1.8 gL−1, and 92.2%, respectively. Ethanol fermentation of the biomass resulted in bioethanol yield and concentration of 84.2% and 4.2 gL−1, respectively. Overall, unsterilized swine wastewater was demonstrated as a cost-effective nutrient source for microalgal cultivation which further increases the economic feasibility and environmental compatibility of bioethanol production with concomitant swine wastewater treatment.

Succinic acid fermentation with immobilized Actinobacillus succinogenes using hydrolysate of carbohydrate-rich microalgal biomass

This work aimed to study the efficiency of polyvinyl-alcohol-immobilized Actinobacillus succinogenes ATCC55618 for succinic acid (SA) production. Batch fermentation (pH 7, 45% CO2 gas at 0.04 vvm) using glucose (40 g L-1) resulted in SA titer, 26.7 g L-1; productivity, 3.33 g L-1h−1; yield, 0.621 g g−1. Fed-batch mode with cyclic extrication of SA from the medium markedly enhanced the yield to 0.699 g g−1 and concentration to 59.5 g L-1. Batch fermentation using sugars derived from Chlorella vulgaris ESP-31 without yeast extract gave a SA productivity, concentration, and yield of 1.82 g L-1h−1, 36.1 g L-1, and 0.720 g g−1, respectively. Furthermore, continuous fermentation (at 6 h HRT) with microalgal sugar improved the productivity and yield to 3.53 g L-1h−1 and 0.62 g g−1, respectively, which is comparable to those obtained by using glucose. This study reports the highest productivity for SA fermentation using microalgae-derived sugars.

Effects of dry and wet torrefaction pretreatment on microalgae pyrolysis analyzed by TG-FTIR and double-shot Py-GC/MS

TG-FTIR and double-shot Py-GC/MS were executed to investigate the effects of torrefaction pretreatment on microalga (Chlorella vulgaris ESP-31) pyrolysis. TG-FTIR was performed to analyze the pyrolysis and combustion gas of raw and wet torrefied microalgae, whereas double-shot Py-GC/MS was applied to investigate the product distributions of single and two-stage thermal degradation of the microalgae. From the result, wet torrefaction successfully eliminated the release of CO in the pyrolysis gas. The highest generation of C–H during pyrolysis was achieved by the microalgae pretreated with dilute sulfuric acid. In the combustion gas, the intensity of O–H absorption band was removed in the first stage after wet torrefaction. The Py-GC/MS analysis revealed that the fatty acids (48.22%) were the dominant component in the bio-oil derived from the microalgae pretreated by the dilute sulfuric acid in wet torrefaction. Meanwhile, the productivity of carbohydrate-derived products (anhydrous sugars) decreased from 18.58 to 0.39% in the pyrolytic bio-oil after the wet torrefaction pretreatment. In contrast, carbohydrate- and lipid-derived products were decreased in the bio-oil after the dry torrefaction pretreatment. Similarly, microwave-assisted wet torrefaction in sulfuric acid is an effective pretreatment technique to produce high-quality pyrolytic bio-oil for biofuel production.

Production of microalgal biochar and reducing sugar using wet torrefaction with microwave-assisted heating and acid hydrolysis pretreatment

This study employed the microwave-assisted acid hydrolysis pretreatment using wet torrefaction on two indigenous microalgae, Chlorella vulgaris ESP-31 and Chlorella sp. GD with different biomass composition to investigate the yields of solid biochar and total reducing sugar in the liquid hydrolysate. Operating conditions at low temperatures (160, 170 °C) with short holding time (5, 10 min) under several concentrations of diluted acid medium (0, 0.1 and 0.2 M) were carried out to investigate the torrefaction severity effects towards the properties of the solid and liquid products. The highest biochar yields of 54.5% and 74.6% are obtained from C. vulgaris ESP-31 and Chlorella sp. GD, respectively under the wet torrefaction conditions with an improvement in the properties for fuel and value-added environmental application. The highest total reducing sugar concentration of 98.11 g/L and 12.08 g/L are obtained in C. vulgaris ESP-31 and Chlorella sp. GD liquid hydrolysates, respectively after acid hydrolysis pretreatment. With the co-production of high total reducing sugar in the liquid hydrolysate that can be utilized for bioethanol production and solid biochar as another value-added product, the acid hydrolysis pretreatment using wet torrefaction can be one of the conversion technologies towards the application of renewable energy production.

Exploring fermentation strategies for enhanced lactic acid production with polyvinyl alcohol-immobilized Lactobacillus plantarum 23 using microalgae as feedstock

Lactic acid (LA) fermentation was conducted with suspended and immobilized cells of an isolated Lactobacillus plantarum 23 strain using various fermentation strategies. Glucose and an alternative, relatively inexpensive carbon source - the hydrolysate of microalga Chlorella vulgaris ESP-31, were used as the carbon source. Batch fermentation using immobilized cells of L. plantarum 23 could enhance LA titer and yield by 43% and 39%, respectively, when compared with the suspended culture. Fed-batch culture integrated with in situ LA removal via ion exchange raised LA productivity by 72% by overcoming product inhibition. The highest LA productivity from glucose with PVA immobilized cells was 14.22 g/L/h, achieved under continuous operation at 50% w/v loading of immobilized beads and hydraulic retention time (HRT) of 2 h. PVA immobilized L. plantarum 23 could also use microalgal hydrolysate as the renewable carbon source, and the highest LA productivity was 9.93 g/L/h under continuous fermentation at 4 h HRT.

Microwave-assisted wet torrefaction of microalgae under various acids for coproduction of biochar and sugar

Wet torrefaction is a promising method to converts the high moisture microalgae to biofuel. In this study, the microalgae were torrefied in water or dilute acid solutions with the aid of microwaves irradiation. The reaction temperature and heating time were fixed at 160 °C and 10 min. The effects of sulfuric, phosphorus, and succinic acids on two different microalgae species (Chlorella vulgaris ESP-31 and FSP-E) were investigated. As a result, the disruption of the microalga FSP-E (high protein) was not notable in the acidic solution. The higher heating value of wet torrefied microalga ESP-31 (high carbohydrate) in succinic acid was enhanced up to 40% with at least 45% of energy yield. The use of 0.1 M of phosphorus acid in wet torrefaction produced the highest ash content of 1.61 and 11.60 wt% for microalgae ESP-31 and FSP-E, respectively. Thermogravimetric analysis revealed that the carbohydrate content of microalga ESP-31 has the highest degradation in sulfuric acid solution. In contrast, crystalline cellulose in the microalgae is hardly affected by the wet torrefaction process in low-temperature acidic solution. In terms of liquid product, a maximum glucose extraction of 35.39 g/L occurred with the use of 0.1 M of sulfuric acid. In conclusion, biochar produced using organic acid is desirable as solid fuel, whereas the use of sulfuric acid is more suitable to produce sugar for bioethanol production.

Examination of indigenous microalgal species for maximal protein synthesis

The expanding aquaculture industry increases the prices of fishmeal, the main protein source in fish diet. A promising alternative is microalgal protein. Therefore, we investigated the protein production capacities of green microalgae Chlorella sorokiniana CY1 and Chlorella vulgaris ESP-31. After optimization, the maximum biomass and protein productivities of Chlorella sorokiniana CY1 reached high values of 4.35 ± 0.09 and 0.856 ± 0.025 g/L/d, while that of Chlorella vulgaris ESP-31 also reached high values of 4.636 ± 0.10 and 0.946 ± 0.065 g/L/d. The cultivation time for both species was only 2 days, wherein Chlorella sorokiniana CY1 and Chlorella vulgaris ESP-31 amassed moderate protein contents of 25.9 ± 1.3% and 26.8 ± 1.3%. The optimum conditions for both species were 50% initial nitrate concentration of Basal medium, 5% CO2 aeration, and 750 μmol/m2/s light intensity. The high biomass and protein productivities of both species indicated their capability as potential protein sources.

Isolation and characterization of Chlorella sp. mutants with enhanced thermo- and CO2 tolerances for CO2 sequestration and utilization of flue gases

BackgroundThe increasing emission of flue gas from industrial plants contributes to environmental pollution, global warming, and climate change. Microalgae have been considered excellent biological materials for flue gas removal, particularly CO2 mitigation. However, tolerance to high temperatures is also critical for outdoor microalgal mass cultivation. Therefore, flue gas- and thermo-tolerant mutants of Chlorella vulgaris ESP-31 were generated and characterized for their ability to grow under various conditions.ResultsIn this study, we obtained two CO2- and thermo-tolerant mutants of Chlorella vulgaris ESP-31, namely, 283 and 359, with enhanced CO2 tolerance and thermo-tolerance by using N-methyl-N-nitro-N-nitrosoguanidine (NTG) mutagenesis followed by screening at high temperature and under high CO2 conditions with the w-zipper pouch selection method. The two mutants exhibited higher photosynthetic activity and biomass productivity than that of the ESP-31 wild type. More importantly, the mutants were able to grow at high temperature (40 °C) and a high concentration of simulated flue gas (25% CO2, 80–90 ppm SO2, 90–100 ppm NO) and showed higher carbohydrate and lipid contents than did the ESP-31 wild type.ConclusionsThe two thermo- and flue gas-tolerant mutants of Chlorella vulgaris ESP-31 were useful for CO2 mitigation from flue gas under heated conditions and for the production of carbohydrates and biodiesel directly using CO2 from flue gas.

Effect of Wet Torrefaction on Thermal Decomposition Behavior of Microalga Chlorella vulgaris ESP-31

Abstract In this work, thermal decompositions of wet torrefied microalga during pyrolysis and combustion are investigated. Microalga Chlorella vulgaris ESP-31 was first subjected to wet torrefaction with microwave-assisted heating. Then, the thermal decompositions of the raw and torrefied microalgae are studied by means of a thermogravimetric analyzer in nitrogen and synthetic air to simulate pyrolysis and combustion process, respectively. The results show that carbohydrate and protein are degraded to some extent during WT. In addition, thermal reactivity of lipid is also changed after WT. The changes in the microalgal composition affect the intensity and location of the corresponding peaks during pyrolysis and combustion. Moreover, the char produced from the raw microalga is more reactive and less stable than those from the torrefied microlagae.

Gasification kinetics of raw and wet-torrefied microalgae Chlorella vulgaris ESP-31 in carbon dioxide

This study aims at investigating the gasification behavior and kinetics of microalga Chlorella vulgaris ESP-31 before and after wet torrefaction. The raw and wet-torrefied microalgae were first gasified in a thermogravimetric analyzer under a continuous CO2 flow. Thereafter, the obtained thermogravimetric data were modeled for kinetic study, employing a seven-parallel-reaction mechanism. The decomposition of the microalgae in CO2 shows two reactive stages: devolatilization with two peaks and gasification with a peak accompanied by a shoulder, and the thermal decomposition of components in the samples can be clearly identified. Increasing wet torrefaction temperature lowers the height of the major devolatilization peak but enhances the height of the minor one. Moreover, the kinetic evaluation reveals that wet torrefaction affects most of the kinetic parameters of the microalgal components. Furthermore, wet torrefaction temperature influences the kinetic parameters of carbohydrate and lipid, but not on those of protein, “others”, and chars.

A comprehensive study on pyrolysis kinetics of microalgal biomass

Pyrolysis of microalgal biomass for biofuels production has attracted much attention. However, detailed degradation mechanism and kinetics of the process have not been fully explored yet. In this study, a non-isothermal pyrolysis of microalga Chlorella vulgaris ESP-31 is thermogravimetrically investigated. Several kinetic models, from a single reaction to seven parallel reactions, are tested to fit the experimental pyrolysis data for finding out the optimal pyrolysis model. The results show that the pyrolysis behavior of the microalga is somewhat different from that of lignocellulosic biomass, stemming from the inherent difference in their compositions. Overall, the kinetic modeling processes show that increasing the number of reactions improves the model fit quality. Curve fitting results indicate that the models consisting of three and less than three reactions are not suitable for microalga pyrolysis. The four-reaction model, via considering the pyrolysis of carbohydrate, protein, lipid and others, can be employed for modeling the thermal degradation; however, it cannot precisely predict the thermal degradation of the shoulder and the small peak. The conducted seven-reaction model further partitions the decomposition processes of carbohydrate and protein into two stages, and explains the thermal degradation well. The model indicates that the devolatilization peak is attributed to the combined degradation of Protein I and Carbohydrate II. The seven-reaction model offers the highest fit quality and is thus recommended for predicting the microalga pyrolysis processes.

Wet torrefaction of microalga Chlorella vulgaris ESP-31 with microwave-assisted heating

Microalgae are a prime source of third generation biofuels. Many thermochemical processes can be applied to convert them into fuels and other valuable products. However, some types of microalgae are characterized by very high moisture and ash contents, thereby causing several problems in further conversion processes. This study presents wet torrefaction (WT) as a promising pretreatment method to overcome the aforementioned drawbacks coupled with microalgal biomass. For this purpose, a microwave-assisted heating system was used for WT of microalga Chlorella vulgaris ESP-31 at different reaction temperatures (160, 170, and 180°C) and durations (5, 10, and 30min). The results show several improvements in the fuel properties of the microalga after WT such as increased calorific value and hydrophobicity as well as reduced ash content. A correlation in terms of elemental analysis can be adopted to predict the higher heating value of the torrefied microalga. The structure analysis by Fourier transform infrared (FT-IR) spectroscopy reveals that the carbohydrate content in the torrefied microalgae is lowered, whereas their protein and lipid contents are increased if the WT extent is not severe. However, the protein and lipid contents are reduced significantly at more severe WT conditions. The thermogravimetric analysis shows that the torrefied microalgae have lower ignition temperatures but higher burnout temperatures than the raw microalga, revealing significant impact of WT on the combustion reactivity of the microalga. Overall, the calorific value of the microalga can be intensified up to 21%, and at least 61.5% of energy in the biomass is retained after WT.

Torrefaction operation and optimization of microalga residue for energy densification and utilization

Abstract The torrefaction characteristics of a microalga (Chlorella vulgaris ESP-31) residue in inert (N2) and non-inert (CO2) atmospheres at temperatures of 200–300 °C with the durations of 15–60 min are investigated. A parameter of torrefaction severity index (TSI) is employed to account for the thermal degradation phenomena. The results indicate that the enhancement factor of higher heating value, energy yield, and atomic H/C and O/C ratios versus TSI are strongly characterized by a linear relationship. The solid and energy yields of the residue torrefied in CO2 are lower than in N2 inasmuch as the thermal degradation in the former is more active, presumably due to the intensified reaction of CO2 with volatile matters in the biomass. At a given energy yield, the microalga residue torrefied at a lower temperature accompanied by a longer duration results in a fuel with higher energy densification and lower solid yield, thereby rendering the better torrefaction quality. On the other hand, a higher efficiency of energy utilization for upgrading the biomass can be achieved at a higher temperature along with a shorter duration. It is thus concluded that the optimization of torrefaction operation depends on the requirement of energy densification or energy utilization on fuel.

Strategies to Improve Oil/Lipid Production of Microalgae in Outdoor Cultivation Using Vertical Tubular-type Photobioreactors

The indoor laboratory-scale microalgae culture was elevated to 50 liter in outdoor photobioreactors for the cultivation of an oil-rich microalga, Chlorella vulgaris ESP-31. Under phototrophic and photoheterotrophic conditions using CO2 and acetic acid as carbon source, respectively, the lipid productivity and lipid content obtained were 30-31mg/L/d and 35-44%, respectively. The effect of inoculum sizes on the performance of biomass and lipid production under phototrophic cultivation was also investigated. The lipid productivity of C. vulgaris ESP-31 was further improved to 47.6mg/L/d when a higher inoculum size of 0.70g/L was used. Finally, to avoid severe contamination problem during outdoor cultivation in the summer time, a two-stage lipid accumulation strategy was employed. The results show that the proposed two-stage process was able to avoid the bacterial contamination and enhanced the lipid content and lipid productivity of Chlorella vulgaris ESP-31.

Microalgae harvesting and subsequent biodiesel conversion

Chlorella vulgaris ESP-31 containing 22.7% lipid was harvested by coagulation (using chitosan and polyaluminium chloride (PACl) as the coagulants) and centrifugation. The harvested ESP-31 was directly employed as the oil source for biodiesel production via transesterification catalyzed by immobilized Burkholderia lipase and by a synthesized solid catalyst (SrO/SiO2). Both enzymatic and chemical transesterification were significantly inhibited in the presence of PACl, while the immobilized lipase worked well with wet chitosan-coagulated ESP-31, giving a high biodiesel conversion of 97.6% w/w oil, which is at a level comparable to that of biodiesel conversion from centrifugation-harvested microalgae (97.1% w/w oil). The immobilized lipase can be repeatedly used for three cycles without significant loss of its activity. The solid catalyst SrO/SiO2 worked well with water-removed centrifuged ESP-31 with a biodiesel conversion of 80% w/w oil, but the conversion became lower (55.7-61.4% w/w oil) when using water-removed chitosan-coagulated ESP-31 as the oil source.

PH-stat photoheterotrophic cultivation of indigenous Chlorella vulgaris ESP-31 for biomass and lipid production using acetic acid as the carbon source

The growth and lipid content of an isolated microalga Chlorella vulgaris ESP-31 were investigated under photoheterotrophic cultivation with different carbon sources (glucose, fructose, sucrose, glycerol, sodium acetate and acetic acid). In the absence of pH control, growing C. vulgaris ESP-31 on glucose obtained the highest biomass concentration (3.5g/L) and lipid content (26%). By controlling pH at 8.5, the growth on fructose and sodium acetate was improved, obtaining a biomass concentration of 3.2–3.6g/L and a lipid content of 24–25%. Moreover, a fed-batch operation with pH-stat feeding of acetic acid was employed to enhance biomass and lipid production. When the pH-stat culture was conducted at pH 7.0–7.5 with acetic acid feeding, the best photoheterotrophic growth performance was obtained, resulting in the highest biomass yield, lipid content, and lipid productivity of 0.68g/g CH3COOH, 50%, and 78mg/L/d, respectively. Regardless of the carbon sources used, the fatty acid profile of the microalgal lipid did not change significantly, as the lipid comprises over 60–80% of saturated fatty acids (mainly palmitic acid (C16:0) and stearic acid (C18:0)) and monounsaturated acids (mainly oleic acid (C18:1)). This lipid composition is suitable for the use in biodiesel synthesis.

Enzymatic transesterification of microalgal oil from Chlorella vulgaris ESP-31 for biodiesel synthesis using immobilized Burkholderia lipase

An indigenous microalga Chlorella vulgaris ESP-31 grown in an outdoor tubular photobioreactor with CO2 aeration obtained a high oil content of up to 63.2%. The microalgal oil was then converted to biodiesel by enzymatic transesterification using an immobilized lipase originating from Burkholderia sp. C20. The conversion of the microalgae oil to biodiesel was conducted by transesterification of the extracted microalgal oil (M-I) and by transesterification directly using disrupted microalgal biomass (M-II). The results show that M-II achieved higher biodiesel conversion (97.3wt% oil) than M-I (72.1wt% oil). The immobilized lipase worked well when using wet microalgal biomass (up to 71% water content) as the oil substrate. The immobilized lipase also tolerated a high methanol to oil molar ratio (>67.93) when using the M-II approach, and can be repeatedly used for six cycles (or 288h) without significant loss of its original activity.

Effects of cultivation conditions and media composition on cell growth and lipid productivity of indigenous microalga Chlorella vulgaris ESP-31

The growth and lipid productivity of an isolated microalga Chlorella vulgaris ESP-31 were investigated under different media and cultivation conditions, including phototrophic growth (NaHCO 3 or CO 2, with light), heterotrophic growth (glucose, without light), photoheterotrophic growth (glucose, with light) and mixotrophic growth (glucose and CO 2, with light). C. vulgaris ESP-31 preferred to grow under phototrophic (CO 2), photoheterotrophic and mixotrophic conditions on nitrogen-rich medium (i.e., Basal medium and Modified Bristol’s medium), reaching a biomass concentration of 2–5 g/l. The growth on nitrogen-limiting MBL medium resulted in higher lipid accumulation (20–53%) but slower growth rate. Higher lipid content (40–53%) and higher lipid productivity (67–144 mg/l/d) were obtained under mixotrophic cultivation with all the culture media used. The fatty acid composition of the microalgal lipid comprises over 60–68% of saturated fatty acids (i.e., palmitic acid (C16:0), stearic acid (C18:0)) and monounsaturated acids (i.e., oleic acid (C18:1)). This lipid composition is suitable for biodiesel production.

Nitrogen starvation strategies and photobioreactor design for enhancing lipid content and lipid production of a newly isolated microalga Chlorella vulgaris ESP‐31: Implications for biofuels

Microalgae are recognized for serving as a sustainable source for biodiesel production. This study investigated the effect of nitrogen starvation strategies and photobioreactor design on the performance of lipid production and of CO(2) fixation of an indigenous microalga Chlorella vulgaris ESP-31. Comparison of single-stage and two-stage nitrogen starvation strategies shows that single-stage cultivation on basal medium with low initial nitrogen source concentration (i.e., 0.313 g/L KNO(3)) was the most effective approach to enhance microalgal lipid production, attaining a lipid productivity of 78 mg/L/d and a lipid content of 55.9%. The lipid productivity of C. vulgaris ESP-31 was further upgraded to 132.4 mg/L/d when it was grown in a vertical tubular photobioreactor with a high surface to volume ratio of 109.3 m(2)/m(3) . The high lipid productivity was also accompanied by fixation of 6.36 g CO(2) during the 10-day photoautotrophic growth with a CO(2) fixation rate of 430 mg/L/d. Analysis of fatty acid composition of the microalgal lipid indicates that over 65% of fatty acids in the microalgal lipid are saturated [i.e., palmitic acid (C16:0) and stearic acid (C18:0)] and monounsaturated [i.e., oleic acid (C18:1)]. This lipid quality is suitable for biodiesel production.

In this issue

Engineering in Life SciencesVolume 10, Issue 3 p. 188-188 In this issueFree to Read In this issue First published: 16 June 2010 https://doi.org/10.1002/elsc.201090010AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract Comparing curve analysis tools Zavrel et al., Eng. Life Sci. 2010, 10, 191–200. Enzyme kinetic analysis tools either apply algebraic or dynamic parameter estimation of use different approaches for data fitting. The choice of approach and computer program is usually subjective, while it is generally assumed that this choice has no influence on the obtained parameter estimates. However, this assumption has not yet been verified comprehensively. Therefore, authors from Aachen, Germany, have compared five commonly used computer programs with respect to accuracy and minimum data required to obtain accurate parameter estimates: MS-Excel, Origin, Encora, ModelMaker and gPROMS. Using experimental and in silico data of penicillin amidase activity, it was shown that significant differences in the estimated parameter values arise by using different computer programs, especially if the number of data points is low. This could explain different parameter values described in the literature. ……………103 http://dx.doi.org/10.1002/elsc.200900083 Microalgae in the spotlight Yeh and Chang, Eng. Life Sci. 2010, 10, 201–208. Chlorella species are unicellular microalgae commonly found in freshwater. They have various applications as supplements in food, cosmetic and pharmaceutical industries. Especially, the algae-derived lipids are suitable for biodiesel production. The growth of microalgae and the composition of microalgal biomass are highly dependent on the type, source and intensity of light needed for the autotrophic growth of the organism. This study evaluates the effects of light and sodium bicarbonate as an inorganic carbon source for the growth of the indigenous microalga Chlorella vulgaris ESP-31, which was obtained from southern Taiwan. At the determined optimal growth conditions, the resulting microalgal biomass consisted of 25-30% protein, 6-10% carbohydrate, and 30-40% lipid. ……………201 http://dx.doi.org/10.1002/elsc.200900116 Metal ion biosorption Michalak et al., Eng. Life Sci. 2010, 10, 209–217. The interaction of metal cations in aqueous solution with macroalgal biomass is of interest for new biosorption applications. This could, for example, be used for the production of mineral feed additives for livestock on the basis of algae enriched with microelement ions. Here, researchers from Wrocław, Poland, investigate the mechanism of interaction between the cell wall of freshwater macroalga Vaucheria sp. and different metal ions. Many functional groups are capable of cation exchange on the macroalgal surface, including carboxyl, phosphate, hydroxyl or amino group, while carboxyl groups play a dominant role. It is shown that ion exchange is one of the key mechanisms of biosorption. Light metal cations Ca(II), Mg(II), Na(I) and K(I) are exchanged with the microelement cations Cu(II), Mn(II), Zn(II), Co(II) and Cr(III). ……………209 http://dx.doi.org/10.1002/elsc.200900039 Volume10, Issue3June 2010Pages 188-188 RelatedInformation