Braunii Strains Research Articles

Removal of weed algal contamination in cultures of Botryococcus braunii with enlarged colonies using rotifers

We proposed a biological contamination control technology that preyed on and removed only invading weed algae by introducing rotifers into the culture ponds of Botryococcus braunii that had enlarged colonies. Botryococcus braunii strains Showa and Sanshiro belonging to race B were used, and the colonies were grown on a high-salt medium containing 3 g L−1 NaCl. Brachionus calyciflorus, a freshwater rotifer with large prey size, was used as the predator, and Westella sp. was used as the model weed algae. In the mixed culture of B. braunii and B. calyciflorus, the growth rate of B. braunii cultured in Chu13, a freshwater medium, was reduced due to predation by B. calyciflorus. However, enlarged B. braunii cultured in a high-salt concentration medium escaped predation and maintained a growth rate equivalent to or higher than that of the control. In the three trials combining B. braunii, B. calyciflorus, and Westella sp., B. calyciflorus was initially applied such that the ratio of the number of rotifers to the algal density of Westella sp. was 2.0 × 10−6. Under these conditions, the initial growth of Westella sp. was suppressed when using the Showa strain, which showed significant growth. The larger colony size of the Sanshiro strain showed greater proliferation of Westella sp. because its optical density was lower than that of the Showa strain. The growth of the Sanshiro strain was suppressed until day 6, when predation reduced Westella sp. density, but the growth rate recovered thereafter. A model for the optimum number of rotifer inputs, considering the optical density and the number of rotifers remaining in the future, and technology for outdoor cultivation must be developed in the future. We demonstrated the potential of an eco-friendly weed-algae-removal technology that uses a predation ecosystem without using special culture environments or pesticides.

In situ extraction (milking) of the two promising Botryococcus braunii strains Showa and Bot22 under optimized extraction time

In situ extraction or “milking” of microalgae is a promising approach to reduce downstream costs in order to produce low-value substances such as lipids from microalgae in an economical way. Due to its ability to secrete high amounts of long-chain hydrocarbons to an extracellular matrix, the green microalga Botryococcus braunii is suitable for the process of in situ extraction as the cost intensive steps of harvesting, dewatering, and cell disruption could be omitted. Based on a previous study investigating various B. braunii strains in terms of growth, lipid accumulation, and solvent compatibility, the B. braunii strains Showa and Bot22 (both B race) were identified as potential candidates for the process of in situ extraction. In order to prove the suitability of these two strains for the process of in situ extraction, this study first determined the optimal extraction time using short-term in situ extraction over 7 days at different starting biomass concentrations of 1.5 and 2.5 g L−1. Furthermore, both strains were treated applying the optimal extraction time in long-term in situ extractions for 30 days to confirm the results from the short-term extractions. The results indicate a strain-dependent optimal extraction time of 300 min day−1 for strain Showa and 200 min day−1 for strain Bot22. During long-term in situ extraction for 30 days, hydrocarbon productivity was 16.99 mg L−1 day−1 (10.53 mg gDW−1 day−1) for strain Showa and 14.53 mg L−1 day−1 (10.48 mg gDW−1 day−1) for strain Bot22. Furthermore, a direct correlation between hydrocarbon productivity achieved by in situ extraction and the hydrocarbon concentration in the biomass of the respective strain could be established. It could be shown that the consideration of the effective extraction time and the phase boundary area is required to calculate an extraction system independent value for the comparison of different extraction setups.

Identification of suitable Botryococcus braunii strains for non-destructive in situ hydrocarbon extraction

The process of milking microalgae is a promising approach to reduce the downstream costs for the production of valuable substances from microalgae by avoiding the steps of harvest, dewatering, and cell disruption of the common process chain (cultivation, harvesting, dewatering, cell disruption, extraction, purification). The green microalga Botryococcus braunii is particularly suited for this process due to its ability to produce large amounts of long-chain hydrocarbons accumulating in an extracellular matrix. The extracellular location of hydrocarbons is an enormous advantage in comparison with other microalgae that accumulate lipids in intracellular lipid bodies. At present, only a few B. braunii strains (UTEX 572, CCAP 807/2, SAG 807/1, FACHB 357, Bot22, and SCCAP 1761) have been examined for the process of long-term repetitive milking. In order to identify promising candidates for the milking process, twelve different B. braunii strains (SAG 30.81, SAG 807/1, UTEX 572, UTEX 2441, CCAP 807/2, ACOI 58, ACOI 1257, SCCAP K-1489, var. Showa, Bot22, SCCAP K-1761, and CCALA 779) were investigated in terms of growth, lipid accumulation, nutrient uptake, solvent compatibility, and extracellular hydrocarbon extractability. Based on these results, a ranking was defined in view of eligibility for non-destructive hydrocarbon extraction. Results indicate a particular potential for hydrocarbon milking for two of those twelve B. braunii strains. The strain Showa (71 out of 75 ranking points), which has not yet been examined for long-term repetitive milking, and the strain Bot22 (64 out of 75 ranking points) seem to be the most suitable strains for the milking process. They both possess good extractant compatibility including hydrocarbon extractability as well as high biomass and lipid productivity.

Culture study on utilization of phosphite by green microalgae

The continuous decline in phosphorus (P) resources is a serious global issue. Therefore, it is important to develop methods to recover P from waste and wastewater. Most P ores are currently used in the phosphate form in the agriculture industry and in detergents, which results in a large release of phosphates into natural aquatic environments. Much attention has been given to measuring phosphate levels and monitoring water quality, survey, and control of algal phytoplankton dynamics. However, phosphite is oxidized from hypophosphite after plating and discharged as waste, so methods to recycle and reuse phosphite should also be developed. Currently, there is no evidence of phosphite utilization by photosynthetic eukaryotes, including eukaryotic algae. Thus, except for the possible utilization by some bacteria when phosphate is unavailable, the fate of the phosphite that is discharged is mostly unknown. Chlorella vulgaris (NIES-2170), Coccomyxa subellipsoidea (NIES-2166), Scenedesmus obliquus (NIES-2280), and Botryococcus braunii (BOT-22) were cultured in phosphite medium under conditions that prevented phosphate contamination and phosphite oxidation. As a result, the number of C. vulgaris and C. subellipsoidea increased in the phosphite medium, demonstrating the availability of phosphite for the growth of these strains. In particular, the growth of C. vulgaris increased as the phosphite concentration increased. After being cultured for 180 days in photosynthetic conditions, phosphite utilization rates were 32–38%. In contrast, S. obliquus and B. braunii strains did not grow in the phosphite medium. In conclusion, C. subellipsoidea and C. vulgaris utilize phosphite as a P resource, which is a novel finding in photosynthetic eukaryotes. The results of this study may have important implications for the phosphorus redox cycle.

Outdoor open pond batch production of green microalga Botryococcus braunii for high hydrocarbon production: enhanced production with salinity

The aim of this work was to enhance the biodiesel quality and hydrocarbon content of green microalga B. braunii strain KMITL 2 cultivated outdoor under several salinity conditions in a batch production. The enhancement would be such that the microalgal biodiesel qualities met or exceeded the current standard so that it would be a good raw material for biodiesel production. The microalga production was in 300 L open oval ponds, among various salinity levels tested (0–20 ppt), 5 ppt was the best for hydrocarbon production, yielding 54.2 ± 0.9% hydrocarbon content and 5.1 ± 0.4 g L−1 biomass. As the microalga production was scaled up by cultivation in 3,675 L open raceway pond under the 5 ppt condition, the microalga yielded a bit higher hydrocarbon content (58.8 ± 2.9%) but much lower biomass (2.5 ± 0.5 g L−1). The production in both oval and raceway ponds yielded a nearly identical biodiesel property (61.06–67.42 cetane number) which exceeded the value specified in international standards. Therefore, it was concluded that B. braunii strain KMITL 2 can be batch cultivated in an open pond at optimum salinity to yield sufficient hydrocarbon and biomass for biodiesel production.

Detection of the oil-producing microalga Botryococcus braunii in natural freshwater environments by targeting the hydrocarbon biosynthesis gene SSL-3

The green microalga Botryococcus braunii produces hydrocarbon oils at 25–75% of its dry weight and is a promising source of biofuel feedstock. Few studies have examined this species’ ecology in natural habitats, and few wild genetic resources have been collected due to difficulties caused by its low abundance in nature. This study aimed to develop a real-time PCR assay for specific detection and quantification of this alga in natural environments and to quantify spatiotemporal variations of wild B. braunii populations in a tropical pond. We designed PCR primers toward the hydrocarbon biosynthesis gene SSL-3 and examined amplification specificity and PCR efficiency with 70 wild strains newly isolated from various environments. The results demonstrated that this PCR assay specifically amplified B. braunii DNA, especially that of B-race strains, and can be widely used to detect wild B. braunii strains in temperate and tropical habitats. Field-testing in a tropical pond suggested a diurnal change in the abundance of B. braunii in surface water and found B. braunii not only in surface water, but also at 1–1.5 m deep and in bottom sediments. This method can contribute to efficient genetic resource exploitations and may also help elucidate the unknown ecology of B. braunii.

Associated bacteria of Botryococcus braunii (Chlorophyta).

Botryococcus braunii (Chlorophyta) is a green microalga known for producing hydrocarbons and exopolysaccharides (EPS). Improving the biomass productivity of B. braunii and hence, the productivity of the hydrocarbons and of the EPS, will make B. braunii more attractive for industries. Microalgae usually cohabit with bacteria which leads to the formation of species-specific communities with environmental and biological advantages. Bacteria have been found and identified with a few B. braunii strains, but little is known about the bacterial community across the different strains. A better knowledge of the bacterial community of B. braunii will help to optimize the biomass productivity, hydrocarbons, and EPS accumulation. To better understand the bacterial community diversity of B. braunii, we screened 12 strains from culture collections. Using 16S rRNA gene analysis by MiSeq we described the bacterial diversity across 12 B. braunii strains and identified possible shared communities. We found three bacterial families common to all strains: Rhizobiaceae, Bradyrhizobiaceae, and Comamonadaceae. Additionally, the results also suggest that each strain has its own specific bacteria that may be the result of long-term isolated culture.

Characterization of the squalene-rich Botryococcus braunii Abt02 strain

Botryococcus braunii is widely studied due to its high hydrocarbon content. In this study, B. braunii Abt02 was subjected to several analyses, including cytological observation, hydrocarbon composition analysis by gas chromatography mass spectrometry (GC-MS), phylogenetic identification using known races (A, B and L) of B. braunii strains based on their 18S rDNA sequences, and qPCR-based investigation of transcript accumulation levels of hydrocarbon biosynthesis-related enzymes (DXS, MCS, DLS, SQS) during different growth phases (lag phase, log phase, early stationary growth phase, late stationary growth phase) under nitrogen-replete and nitrogen-depleted growth conditions, respectively. Based on cytological observation and on the 18S rDNA phylogenetic analysis, strain Abt02 was assigned to race B. Analysis of the strain’s chemical composition showed that the B. braunii Abt02 contained high levels of hydrocarbons, which accounted for 43.75% of the cell’s dry weight. Of these hydrocarbons, squalene and its derivatives accounted for up to 87.54%. In addition, all four enzymes investigated were expressed at higher levels during the log growth phase under nitrogen depleted conditions than under nitrogen replete conditions.

Lipidomic analysis of Botryococcus (Trebouxiophyceae, Chlorophyta) - Identification of lipid classes containing very long chain fatty acids by offline two-dimensional LC-tandem MS

Very long chain fatty acids (VLCFAs) were identified in four strains of the green alga Botryococcus braunii (Trebouxiophyceae). The algae contained a series of monoenoic fatty acids up to triacontenoic acid and further VLCFAs in amounts around 1% of total fatty acids. The separation of lipid classes using hydrophilic interaction chromatography revealed that the most abundant VLCFAs (28:2, 28:1 and 28:0) were contained in neutral lipids (triacylglycerols and/or diacylglycerols) and in phospholipids (phosphatidic acid and/or phosphatidylcholine). Using non-aqueous reversed-phase liquid chromatography tandem mass spectrometry (NARP-LC/MS2) of the appropriate collected fractions, molecular species of triacylglycerols containing one or two VLCFAs were described and phosphatidylcholines containing VLCFAs were separated for the first time. Because the presence of Botryosphaerella sudetica (Chlorophyceae) as contaminant of Botryococcus braunii strain Droop 1950/807-1 placed some doubts on the results of previous studies, a strain of this green alga of was also analyzed. In contrast to Botryococcus, C16, a substantially lower proportion of C18 polyunsaturated fatty acids and no VLCFAs were detected in Botryosphaerella.

Wastewater treatment by microalgae can generate high quality biodiesel feedstock

Botryococcus braunii strains are high-lipid producers. Despite this, their use as biodiesel feedstock is limited by their slow growth, which increases production costs. B. braunii wastewater bioremediation power, however, may be able to overcome this problem. This research evaluated the performance of two strains (UTEX-USA and IBL-Brazil) grown in pre-treated (influent) and treated (effluent) wastewater. The goal was to optimize algal-productivity and wastewater treatment in order to provide biomass rich in high-quality oil for biodiesel. The standard CHU-medium was used as control. Phosphorus was 100% removed in all treatments for both strains. Nitrogen removal was higher in wastewater (61–65%) than in CHU medium (48 and 61%), respectively for UTEX and IBL strains. Cultivation in the effluent generated higher biomass and lipid productivity for the UTEX strain, while the influent was the best for the IBL strain. The composition of the fatty-acids produced by Botryococcus was used to estimate the biodiesel quality. Hence, the biodiesels may have good fuel quality (high ignition and combustion efficiency) but limited application at low temperatures. The composition of fatty-acids, however, can be optimized by growing or mixing strategies. Therefore, Botryococcus braunii is a potential source for high quality biodiesel production.

Application of NaCl for Biodiesel Components Production by Botryococcus braunii

Objectives: To reveal the potential use of NaCl for cultivation of Botryococcus braunii on commercial basis for bioenergy production. Methods/Analysis: The experiments were performed with different amounts of NaCl, two Botryococcus braunii strains and Anopheles mosquito larvae under controlled conditions. In order to find any role of hydrocarbons or lipids for killing of larvae, experiments with the algal extracts prepared in two solvents i.e., n-hexane and chloroform:methanol (2:1), were conducted. Hydrocarbons and lipids were analyzed by Gas Chromatography-Mass Spectrometry. Findings: Oil and hydrocarbon content in Botryococcus braunii were enhanced in Chu-13 medium supplemented with 0.5 M NaCl and growth was also not much affected. Relative ratios of different kinds of lipids and hydrocarbons produced by the algal strains were also affected significantly. Additionally, medium supplemented with NaCl was found to be fatal to Anopheles mosquito larvae which cause severe losses of algal biomass particularly during mosquito breeding season during outdoor algal cultivation. Novelty/Improvement: Finding of killing of Anopheles mosquito larvae and improvement in the quantity and quality of hydrocarbons and lipids by NaCl in nutrient medium can be probably exploited for the cultivation of Botryococcus braunii for biodiesel production.

Botryococcus braunii strains compared for biomass productivity, hydrocarbon and carbohydrate content

Botryococcus braunii can produce both long-chain hydrocarbons as well as carbohydrates in large quantities, and is therefore a promising industrial organism for the production of biopolymer building blocks. Many studies describe the use of different strains of Botryococcus braunii but differences in handling and cultivation conditions make the comparison between strains difficult. In this study, 16 B. braunii strains obtained from six culture collections were compared for their biomass productivity and hydrocarbon and carbohydrate content. Biomass productivity was highest for AC768 strain with 1.8gL−1day−1, while hydrocarbon production ranged from none to up to 42% per gram biomass dry weight, with Showa showing the highest hydrocarbon content followed by AC761. The total carbohydrate content varied from 20% to 76% per gram of the biomass dry weight, with CCALA777 as the highest producer. Glucose and galactose are the main monosaccharides in most strains and fucose content reached 463mgL−1 in CCALA778.

Molecular phylogeny of Botryococcus braunii strains (race A) – An integrative approach

Botryococcus braunii is a green colonial microalga which produces large quantities of liquid hydrocarbons similar to fossil petroleum. Exploring Botryococcus genus diversity entailed morphological, biochemical and phylogenetic studies. The majority of scientific literature specifies B. braunii as the only species with strains classified in three chemical races (A, B and L) which superpose the phylogenetic clusters built on 18S rDNA sequences. The cohesion of data provided by the three main research directions relies on the integrative analysis of the Botryococcus strains. The present work addresses the diversity of B. braunii race A strains by taking into account the morphology, the hydrocarbon and fatty acid profiles, and the phylogeny of 10 strains, isolated from several Romanian aquatic environments. The newly sequenced B. braunii strains increased the resolution of the analyses and yielded at least two distinct phylogenetic clades within race A cluster. This outcome was sustained by the genetic information coded by the 18S rRNA genes and both sequence- and sequence-structure analysis of ITS2. The Compensatory Base Changes occurrence within the secondary structure of ITS2 and the presence of one intron in the 18S rDNA sequences gave extra credibility to our phylogenetic results.

MATHEMATICAL MODELLING OF DRYING OF CHLORELLA SP., NEOCHLORIS CONJUNCTA AND BOTRYOCOCCUS BRAUNII AT DIFFERENT DRYING CONDITIONS

Drying is one of the most important process in the cultivation of microalgae. Performance of drying depends on appropriate drying methods. This study aimed (1) to determine the effect of different drying methods on the Chlorella sp., Neochloris conjuncta, and Botryococcus braunii strains and (2) to identify the most suitable model for drying methods. Chlorella sp., Neochloris conjuncta and Botryococcus braunii cultures were grown in basal medium in raceways at the greenhouse condition in Isparta province. During experiment, air temperature and relative humidity, wind speed, solar irradiance, wet and dry mass and temperature of microalgae biomass were measured. Drying applications continued for approximately 3 days. Microalgae were dried at solar tunnel, outdoor, and greenhouse conditions. Furthermore, the effect of drying methods such as open sun, solar tunnel, and greenhouse drying on drying time, and drying ratio of microalgae have been investigated. The drying data were applied to ten different mathematical models, namely, Newton, Page, Henderson and Pabis, Logarithmic, Midilli and Kucuk, Wang and Singh, Two Term, Two Term Exponential, Weibull and Logistic Equation Models. The performance of these models were compared according to the coefficient of determination, standard error of estimate and residual sum of squares, between the observed and predicted moisture ratios. Results showed that the Weibull equation gave the best prediction to the drying kinetics evidenced by coefficient of determination ranging from 0.9959 – 0.9992 for all drying methods. In addition, solar tunnel drying method has been determined to be the most suitable one among tested methods for drying of microalgae. Key words: Chlorella sp., Neochloris conjuncta, Botryococcus braunii, drying, mathematical modelling, microalgae

Application of nutrient stress conditions for hydrocarbon and oil production by Botryococcus braunii

ABSTRACTThe influence of main nutrient stress conditions KNO3, MgSO4, K2HPO4 and KCl on biofuel production from biomass by two Botryococcus braunii strains has been investigated. Low concentrations of KNO3 and MgSO4 exhibited positive effect on hydrocarbon, oil contents and their relative ratios without much affecting the growth. Most of the saturated hydrocarbons were identified in the range of C15 to C44, the major ones being C17H34, C19H38, C21H44, C24H50 and C27H56. Fatty acids ranged from C12 to C28, with palmitic, linoleic, oleic and stearic acids being the major ones. The relative proportion of the desirable biofuel component, palmitic acid, was significantly increased under NO31−, PO43− and potassium stress conditions. These findings suggest that monitoring of concentration of a few nutrients may enhance the quantity and desirable types of biofuel components together with substantial growth of Botryococcus braunii for bioenergy production and for commercial large scale cultivation.

Towards the commercialization of Botryococcus braunii for triterpenoid production

Botryococcus braunii can accumulate unusually high levels of triterpenoid hydrocarbons making it a potential source of high value chemicals. However, its commercial application is hampered by its slow growth and lack of large-scale studies of triterpenoid hydrocarbon production. This study investigated hydrocarbon production in two race B of B. braunii strains, Overjuyo-3 and Kossou-4, at 25 °C in 500 L open tanks under artificial lighting in modified BG11 medium over 60 days. Maximum growth was reached by 40 days with Overjuyo-3 producing more biomass (3.05 g L(-1)) than Kossou-4 (2.55 g L(-1)). However, Kossou-4 produced more oil (0.75 g L(-1)) and triterpenoid hydrocarbons (C30-C34; 50 % of oil weight) compared to 0.63 g L(-1) of oil in Overjuyo-3 with triterpenoid hydrocarbons making up 29 % of oil weight. This research demonstrates for the first time that large-scale production of high value triterpenoid hydrocarbon for commercial application is feasible with Kossou-4 strain.

Transcriptomic analysis of a moderately growing subisolate Botryococcus braunii 779 (Chlorophyta) in response to nitrogen deprivation.

BackgroundThe colonial microalga Botryococcus braunii has been brought to people’s attention for its conspicuous ability to accumulate a variety of lipids including hydrocarbons. B. braunii strains are classified into 3 races based on the types of hydrocarbons. A and B races are known to accumulate high level of lipids. However, their extreme slow growth rate has impeded its application for renewable biofuel production.ResultsIn this study, we report the transcriptomic response of a moderately growing subisolate from the culture of Botryococcus sp. CCALA-779 upon nitrogen deprivation (ND). We show that the subisolate has an average growth rate of 0.52 g l−1 day−1 under photoautotrophic growth conditions and lipid content is enhanced to 75 % of CDW upon ND. Both rDNA sequence and hydrocarbon composition analyses indicate that the subisolate belongs to A race B. braunii. Hence, it is designated as B. braunii 779. We show that B. braunii 779 transcriptome shares homology to majority of the A race but not B race B. braunii ESTs, suggesting that transcriptomes of A race differ from that of B race. We found that many homologous ESTs between A races 779 and Bot-88 are unknown sequences, implying that A race contains many unknown genes. Pathway-based transcriptomic analysis indicates that energy metabolisms are among the top expressed functions in log-phase cells, indicating that the slow growth rate is a result that energy flow is directed to lipid biosynthesis but not population growth. Upon ND, reconfiguration of metabolisms for reducing power is apparent, suggesting that B. braunii 779 is rapidly adapting under ND condition by transcriptomic reprogramming.ConclusionsTaken together, our result shows that the subisolate B. braunii 779, similar to the Gottingen strain, is useful for biofuel production. Difference between transcriptomes of A and B races implies that different races of B. braunii strains belong to different sub-species. Furthermore, there are many novel genes that are unique to A race, suggesting that sequences of many enzymes involved in hydrocarbon biosynthesis are not currently known. We propose that B. braunii transcriptomes provide a rich source for discovery of novel genes involved in hydrocarbon biosynthesis.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-015-0307-y) contains supplementary material, which is available to authorized users.

Assessing the biofuel production potential of Botryococcus braunii strains by sensitive rapid qualitative chemotyping using chemometrically-assisted gas chromatography–mass spectrometry

The microalga Botryococcus braunii has been studied for its hydrocarbon biofuel production potential. The range of the lipids it synthesizes cannot be readily profiled, because their main chemical class standards (long chain alkenes and botryococcenes) are at present unavailable.The aim of this study was to develop a direct, specific GCMS analysis method for the rapid chemotyping of these lipids.The SIM (Selected Ion Monitoring)-GCMS program we developed discriminates classes and subclasses of the targeted molecules through their main chemical motifs identified with fragment ions of specific m/z selected by unsupervised chemometrics.Our validation results indicate that the SIM mode enhanced their detection by significantly increasing the signal-to-noise ratio ca. 20-fold. The profiling results from TL extracts of diverse B. braunii strains show that under the culture conditions tested, these strains could be distinguished by their chemical signatures, which also signaled different culture conditions involving various physiological states. We were able to make a rapid estimate of the biofuel potential of these strains, focusing on alkenes and botryococcenes.The direct injection SIM-GCMS method was successfully applied here for rapid chemotaxonomy, displaying good sensitivity and specificity for new high molecular weight hydrocarbons from B. braunii.

Bio-harvesting and pyrolysis of the microalgae Botryococcus braunii

The microalgae Botryococcus braunii is widely recognized as a potentially important biofuel-feedstock whose commercial exploitation is limited by difficulties with its cultivation and harvesting. In this study, two B. braunii strains, Kossou-4 and Overjuyo-3 were successfully cultured at a 500l-scale for 60-days. Harvesting by bio-flocculation with Aspergillus fumigatus at an optimum ratio of 1:40 of fungus to microalgal culture resulted in up to 98% recovery of biomass in the two strains. Ultimate analysis (C, N, H, S, ash, high heating value) and pyrolysis (analytical and preparative pyrolysis and GC–MS assays) showed that co-harvesting with fungi did not cause any impairment of the feedstock value of the microalgal biomass. This work represents the first report on the successful culturing and harvesting of these strains at a 500l-scale using bio-flocculation. The use of A. fumigatus represents an efficient and economical method for the harvest of B. braunii for biofuel production.

Botryococcus braunii as a Phycoremediation Tool for the Domestic Waste Water Recycling from Cooum River, Chennai, India

The micro algae are the green photosynthetic micro organisms, which are the primary producers of the aquatic ecosystems. The green micro algae have evolved long back approximately two and a half billion years ago and initiated the process of photosynthesis in the world. The Botryococcus braunii is a green photosynthetic micro alga fixes atmospheric CO2 for energy production and it is well known for high quantity of lipid accumulation. Along with normal fatty acids the long chain different types of hydrocarbon production exudates outside of the cells are the characteristic features of this specific micro alga. At the same time, this unique micro alga has been reported to grow well in the sewage waste water and can be used to remove toxic metals and unwanted nutrients from waste water. In this present study, a new and novel strain of Botryococcus braunii has been isolated from the temple ponds around the Chennai city, Tamil Nadu, India. The effective treatment of domestic waste water from different sites around Chennai city using Botryococcus braunii has been well evaluated in this current study. The physiochemical parameters like COD, BOD, electrical conductivity (EC) and ammonia have been removed more than 70% from domestic waste water especially in Adyar River (AR) domestic waste water when compared to other waste water. The growth kinetics of the Botryococcus braunii strain in the domestic waste water AR and NB (Napier’s bridge) have shown good results when compared to other samples. The micro alga B. braunii strain is well known for its high lipid production and which was achieved from the biomass harvested from the domestic waste water sample AR. The total carotenoid content was also found in the micro algal biomass from the sample AR. This overall research study suggested that the implication of some important micro algae for the treatment of waste water can remediate the water resource as well as the biomass yield can be economically useful for many applications.