Exopolysaccharides from the Energy Microalga Strain Botryococcus braunii: Purification, Characterization, and Antioxidant Activity

Botryococcus braunii, a prestigious energy microalga, has recently received widespread attention because it can secrete large amounts of exopolysaccharides (EPS) with potential applications in food, cosmetics, and nutraceuticals. Unfortunately, the insufficiency of research on the bioactivity and structure–activity relationship of B. braunii EPS has impeded the downstream applications. In the present study, alcohol precipitation, deproteinization, and DEAE-cellulose column chromatography were used to extract and purify B. braunii SCS-1905 EPS. It was found that B. braunii SCS-1905 EPS were high-molecular-weight heteropolysaccharides containing uronic acid (7.43–8.83%), protein (2.30–4.04%), and sulfate groups (1.52–1.95%). Additionally, the EPS primarily comprised galactose (52.34–54.12%), glucose (34.60–35.53%), arabinose (9.41–10.32%), and minor amounts of fucose (1.80–1.99%), with the presence of a pyranose ring linked by a β-configurational glycosidic bond. Notably, the antioxidant activity of crude exopolysaccharides (CEPS) was stronger, and the half maximal inhibitory concentration (IC50) for ABTS and hydroxyl radicals was significantly lower than that of deproteinized exopolysaccharides (DEPS). Overall, this study indicated a potential application of B. braunii SCS-1905 EPS as a natural antioxidant. In summary, B. braunii EPS could be used as a potential feedstock for the production of antioxidant health foods.

The Effect of Nutrients Mixture on The Biomass and Lipid Production from Microalgae Botryococcus braunii Mutated by UV-C Rays

Nutrient is one of the most important factors in the growth of microalgae. This research was conducted to study the effect of nutrient mixture on the biomass and lipid production of Botryococcus braunii. Microalgae B. braunii was cultivated in the commercial nutrient medium of agricultural fertilizer combinations of ammonium sulphate (ZA), urea, and triple superphosphate (TSP). Before the cultivation process, B. braunii was exposed to UV-C rays (254 nm) for 3 minutes. The concentration and type of fertilizer as a nitrogen source divided into four types of mixtures, namely FM-1, FM-2, FM-3, and FM-4 were compared with Walne nutrients to study their effects on microalgae growth and lipids. FM-1 consisting of 150 mg/L of ZA, 7.5 mg/L of urea, and 25 mg/L of TSP led to the best growth for native and mutated microalgae strains compared to Walne nutrients and other nutrient mixtures. The mutated microalgae showed less growth than the native microalgae strains. However, the mutation process significantly increased the lipid content in the microalgae. In native microalgae strains, FM-4 consisting of 136.3 mg/L of urea and 50 mg/L of TSP produced the lowest lipid at 8.96%. After being exposed to UV-C rays, the lipids in FM-4 medium increased to 55.11%. The results show that the use of commercial fertilizers and exposure to UV-C rays on microalgae have high potential in preparing lipids as raw material for biodiesel which can be effectively applied in large-scale microalgae cultivation.

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.

In Silico and Cellular Differences Related to the Cell Division Process between the A and B Races of the Colonial Microalga Botryococcus braunii

Botryococcus braunii produce liquid hydrocarbons able to be processed into combustion engine fuels. Depending on the growing conditions, the cell doubling time can be up to 6 days or more, which is a slow growth rate in comparison with other microalgae. Few studies have analyzed the cell cycle of B. braunii. We did a bioinformatic comparison between the protein sequences for retinoblastoma and cyclin-dependent kinases from the A (Yamanaka) and B (Showa) races, with those sequences from other algae and Arabidopsis thaliana. Differences in the number of cyclin-dependent kinases and potential retinoblastoma phosphorylation sites between the A and B races were found. Some cyclin-dependent kinases from both races seemed to be phylogenetically more similar to A. thaliana than to other microalgae. Microscopic observations were done using several staining procedures. Race A colonies, but not race B, showed some multinucleated cells without chlorophyll. An active mitochondrial net was detected in those multinucleated cells, as well as being defined in polyphosphate bodies. These observations suggest differences in the cell division processes between the A and B races of B. braunii.

A Review of the application of the Microalgae Botryococcus braunii in industrial Processes

Las microalgas son microorganismos fotosintéticos los cuales pueden ser eucariotas (algas) o procariotas (cianobacterias) y pueden estar presentes en todos los hábitats de la tierra. Este artículo ofrece una descripción bibliográfica sobre análisis técnicos en la producción industrial de los principales metabolitos extraídos de Botryococcus braunii con el objetivo de analizar, determinar e identificar los avances científicos para la utilización de esta alga como un recurso potencial, por medio de una recopilación bibliométrica de 20 años sobre artículos de investigaciones demostrando gran interés en el campo de las microalgas. Se ha realizado este trabajo con el propósito de averiguar los estudios en el área de la microalga Botryococcus braunii y sus aplicaciones industriales, también determinar los principales metabolitos como hidrocarburos, exopolisacáridos, carotenoides, proteínas, en el aprovechamiento de procesos industriales como materiales, alimentos, productos farmacéuticos, nanopartículas y biocombustibles. Debido a sus vías metabólicas particulares, su adaptabilidad fisiológica y su uso en sistemas de cultivo avanzados, existe un gran potencial para producir sustancias químicas de alto valor a partir de cepas de Botryococcus braunii.

The Relationship of Organic Components to Source Rocks Types Based on Biomarker Data at Central Sumatra Basin

A biomarker study is used to observe the quality level of a hydrocarbon compound deposited on the source rock. The presence of Botryococcus braunii algae, Pediastrum algae, and other lacustrine algae is thought to be a contributing factor to petroleum in lacustrine basins throughout Southeast Asia. Botryococcus braunii is a group of green algae and belongs to the Trebouxiophyceae class. The purpose of this study is to discuss the relationship between organic compounds and the type of source rock in the Central Sumatra Basin. The Central Sumatra Basin is a back-arc basin that develops along the edge of the Sunda shelf in Southeast Asia. This basin was formed by the moving of the submergence of the Indian Ocean plate relative to the North and infiltrates the Asian Continent plate. The data used in this study is taken from several literatures/references in biomarker analysis where qualitative analysis was carried out, such as: matching the readings of compounds contained in the chromatogram and associate them with classification in some existing literatures where the selection of organic components that had an effect on geological analysis was carried out. An explanation of some of the data obtained along with the chromatogram and geological analysis and interpretation can be seen in this paper. Some conclusions can be drawn from this research in the form of qualitative analysis of organic components to define the maturity of the hydrocarbon and suspect the source organic materials of the hydrocarbon in source rocks. The explanation of the main biomarkers that must be considered when analyzing oil or source rock samples is to know the characteristic of the hydrocarbon and correlate it with reaction during the deposition.

Pengaruh Salinitas dan Limbah Cair Tahu pada Konsentrasi yang Berbeda terhadap Pertumbuhan Mikroalga Botryococcus braunii Kutzing

Pertumbuhan mikroalga Botryococcus braunii Kutzing dipengaruhi oleh faktor lingkungan berupa salinitas, suhu, pH, oksigen terlarut (DO), intensitas cahaya dan nutrisi pada media kultivasi. Penelitian ini bertujuan untuk mengkaji pengaruh salinitas dan limbah cair tahu terhadap pertumbuhan mikroalga B. braunii. Perlakuan yang dilakukan dalam penelitian ini yaitu konsentrasi limbah cair tahu 10% dengan salinitas 15‰ (L10S15); limbah cair tahu 10% dengan salinitas 20‰ (L10S20); limbah cair tahu 10% dengan salinitas 25‰ (L10S25); limbah cair tahu 20% dengan salinitas 15‰ (L20S15); limbah cair tahu 20% dengan salinitas 20‰ (L20S20); limbah cair tahu 20% dengan salinitas 25‰ (L20S25); limbah cair tahu 30% dengan salinitas 15‰ (L30S15); limbah cair tahu 30% dengan salinitas 20‰ (L30S20); dan limbah cair tahu 30% dengan salinitas 25‰ (L30S25). Pengamatan yang dilakukan meliputi kepadatan sel dan faktor lingkungan berupa salinitas, suhu, pH, oksigen terlarut, serta kadar N dan P total. Data yang diperoleh diolah menggunakan metode analisis sidik ragam (ANOVA) yang dilanjutkan dengan uji Duncan. Hasil penelitian menunjukkan kepadatan sel tertinggi didapatkan pada perlakuan L10S25 dengan rata-rata kepadatan sel 313x104sel/ml. Secara umum, semakin tinggi limbah cair tahu yang diberikan maka kepadatan sel mikroalga akan semakin rendah.