Different fermentation strategies by Schizochytrium mangrovei strain pq6 to produce feedstock for exploitation of squalene and omega-3 fatty acids (original) (raw)
Related papers
Applied Microbiology and Biotechnology, 2009
The culture protocol of Schizochytrium limacinum SR 21, a known docosahexaenoic acid (DHA) producing marine algae was modified in this study to better fit fermentation parameters, particularly control of dissolved oxygen (DO) to the known reproductive and growth biology of the microorganism. The cultures controlled at 50% DO saturation produced a cell density of 181 million cells/ml, whereas cultures with 10% DO produced only 98.4 million cells/ml. A fixed-agitation rate of 150 rpm resulted in an even lower density of 22.5 million cells/ml. Fifty percent DO saturation level led to a decreased pH, as well as a negative correlation with lipid accumulation, while low oxygen concentration was obligatory for lipid accumulation. This study indicated that high DO was preferred for the cells' reproduction via release of zoospores. Thus, the culture of S. limacinum SR21 should be best divided into two stages: (1) a cell-number-increasing stage in which cell reproduction and cell number increase with little increase in the size and weight of each cell; and (2) a cell-size-increasing stage in which cells stop reproduction but cell size enlarges due to lipids accumulation. With such a protocol, the production of algae biomass and DHA was improved to levels of 37.9 g/L and 6.56 g/L, respectively. The two-stage culture process could be potentially used not only for omega-3 PUFA production, but also in other single cell oil (SCO)-producing processes, including biodiesel production from algae.
Applied Biochemistry and Biotechnology, 2011
In the present study, a novel oleaginous Thraustochytrid containing a high content of docosahexaenoic acid (DHA) was isolated from a mangrove ecosystem in Malaysia. The strain identified as an Aurantiochytrium sp. by 18S rRNA sequencing and named KRS101 used various carbon and nitrogen sources, indicating metabolic versatility. Optimal culture conditions, thus maximizing cell growth, and high levels of lipid and DHA production, were attained using glucose (60 gl −1) as carbon source, corn steep solid (10 gl −1) as nitrogen source, and sea salt (15 gl −1). The highest biomass, lipid, and DHA production of KRS101 upon fed-batch fermentation were 50.2 gl −1 (16.7 gl −1 day −1), 21.8 gl −1 (44% DCW), and 8.8 gl −1 (40% TFA), respectively. Similar values were obtained when a cheap substrate like molasses, rather than glucose, was used as the carbon source (DCW of 52.44 gl −1 , lipid and DHA levels of 20.2 and 8.83 gl −1 , respectively), indicating that production of microbial oils containing high levels of DHA can be produced economically when the novel strain is used.
Isolate of Heterotrophic Microalgae as a Potential Source for Docohexaenoic Acid (Dha)
Marine Research in Indonesia
Docosahexaenoic acid (DHA) is one of essential fatty acids that are beneficial to health. Nowadays, the source of docosahexaenoic acid (DHA) is mainly obtained from fish which are extracted into fish oil products. However, the fish oil products still have some drawbacks in term of purity, acceptable flavor for costumers, and also their not environmental friendly production process. As an alternative solution, heterotrophic microalgae can be used as a potential source for DHA due to their excellence compared to fish oil products. The aim of this study is to isolate the heterotropic microalgae that can produce DHA. The heterotrophic microalgae were isolated from mangrove fallen leaves (Rhizophora apiculata) by using direct planting method. The morphology of pure microalgae colony were observed through light microscope and subsequently fermented for 14 days. Fatty acids were extracted and methylated through direct transesterification method. Identification and quantification of DHA wer...
Applied Sciences
Heterotrophic microalgae are recognized as a source of bioactive compounds. However, there are still some drawbacks for their use at an industrial scale associated with the high cost of glucose, the main carbon source in heterotrophic cultures. In recent years, significant efforts have been made to investigate more sustainable carbon sources to produce biomass. In this study, the capacity of Schizochytrium limacinum to grow on waste-derived volatile fatty acids and the effect that their use produces on biomass and fatty acids profiles were investigated. Acetic, propionic, butyric, valeric and caproic acid were evaluated independently, as well as in a synthetic mixture (VFA). The use of acetic and butyric resulted in a good biomass productivity, while the use of valeric and propionic acid resulted in higher content of odd-chain fatty acids (OCFA), increasingly investigated due to their potential benefits for human health. The use of industrial waste-derived VFA as a potential carbon ...
Applied Sciences
The simultaneous use of crude glycerol and effluent from anaerobic digestate, both wastes derived from the biofuel industry, were tested in the frame of circular economy concept, as potential low-cost nutrient sources for the cultivation of rich in docosahexaenoic acid (DHA) oil microalgae strain Schizochytrium limacinum SR21. Initially, the optimal carbon and nitrogen concentration levels for high S. limacinum biomass and lipids production were determined, in a culture media containing conventional, high cost, organic nitrogen sources (yeast extract and peptone), micronutrients and crude glycerol at varying concentrations. Then, the effect of a culture media composed of crude glycerol (as carbon source) and effluent digestate at varying proportions on biomass productivity, lipid accumulation, proximate composition, carbon assimilation and fatty acid content were determined. It was shown that the biomass and total lipid content increased considerably with varying effluent concentrat...
Renewable Energy
Dark fermentation is an anaerobic digestion process of biowaste, used to produce hydrogen as a fuel, which however releases high amounts of polluting volatile fatty acids in the environment. In order for the process to become more competitive, the acids stream can be utilized through conversion to high added-value docosahexaenoic acid by the microalga Crypthecodinium cohnii. Docosahexaenoic acid is one of the two main omega-3 fatty acids, necessary for human nutrition. The purpose of this work was to optimize the production of omega-3 fatty acids by the cells, utilizing the organic content of a dark fermentation effluent. For that purpose, the effect of different fermentation conditions was examined, such as incubation temperature, nitrogen source and concentration, the addition of chemical modulators, as well as the feeding composition. The volatile fatty acid content of the effluent was totally depleted in a fed-batch culture of the microalga, while the cells accumulated DHA in a percentage of 35.6% of total lipids, when fed with yeast extract or 34.2% when fed with ammonium sulfate. Taking into consideration the economic feasibility of the culture conditions proposed it was concluded that the use of yeast extract could be substituted by the much economic ammonium sulfate.
Polyunsaturated fatty acids production by Schizochytrium sp. isolated from mangrove
2003
Kamlangdee, N. and Fan, K.W. Polyunsaturated fatty acids production by Schizochytrium sp. isolated from mangrove DHA in fatty acid profile with 15:0, 28.7%; 16:0, 21.3%; 18:0, 0.9%; 18:3, 0.2%; 20:4, 0.3%; 20:5, 0.9%; 22:4, 6.7%; 22:6, 36.1%; and others, 9.3%. The salinity range for growth of Schizochytrium isolates was from 0-30‰ with optimum salinity for growth between 20-30‰.
Kasetsart Journal - Natural Science
Polyunsaturated fatty acids including DHA are essential dietary fatty acids. At present, fish oils are a major source, but an alternative supply is needed because of increasing demand and fish dwindling stocks. This need might be satisfied using a thraustochytrids found in mangrove forests of Thailand and identified by 18S rDNA sequencing as either Schizochytrium limacinum or Thraustochytrium aggregatum. S. limacinum was tested in various culture conditions to find the optimal yield of DHA. This culture medium contained 7.5% glucose, 0.5% peptone, 0.5% yeast extract (with either 0.25% soybean meal or 1% skimmed milk) and 0.75% sea salt at 20-30°C. The C:N ratio was about 15:1. The culture was mutated using NTG and one isolate showed high DHA content and also a red pigment identified as astaxanthin by TLC and HPLC. Astaxanthin synthesis peaked on day 6 -10 of incubation in medium containing 2% glucose using shaking flasks at 180 rpm, 25°C, 2 kLux light intensity with a 18:6 h light:dark periods. Six days of incubation yielded the highest yields of both DHA (224.6 mg/l) and astaxanthin (8.9 µg/ml of medium). These results suggested that this microorganism could provide a commercial source of this valuable lipid and pigment.
Journal of Phycology, 2011
Schizochytrium sp. PQ6, a heterotrophic microalga isolated from Phu Quoc (PQ) Island in the Kien Giang province of Vietnam, contains a high amount of docosahexaenoic acid (DHA, C22:6n-3). In this study, the culture conditions are developed to maximize biomass and DHA production. Nucleotide sequence analysis of partial 18S rRNA gene from genomic DNA showed that PQ6 has a phylogenetic relationship close to Schizochytrium mangrovei Raghu-Kumar. The highest growth rate and DHA accumulation of this strain were obtained in 6.0% glucose, 1.0% yeast extract, 50% artificial seawater (ASW), and pH 7 at 28°C. In addition, carbon and nitrogen sources could be replaced by glycerol, ammonium acetate, sodium nitrate, or fertilizer N-P-K. Total lipid content reached 38.67% of dry cell weight (DCW), in which DHA and eicosapentaenoic acid (EPA, C20:5n-3) contents accounted for 43.58% and 0.75% of the total fatty acid (TFA), respectively. In 5 and 10 L fermenters, the cell density, DCW, total lipid content, and maximum DHA yield were 46.50 • 10 6 cells AE mL)1 , 23.7 g AE L)1 , 38.56% of DCW, and 8.71 g AE L)1 (in 5 L fermenter), respectively, and 49.71 • 10 6 cells AE mL)1 , 25.34 g AE L)1 , 46.23% of DCW, and 11.55 g AE L)1 (in 10 L fermenter), respectively. Biomass of PQ6 strain possessed high contents of Na, I, and Fe (167.185, 278.3, and 43.69 mg AE kg)1 DCW, respectively). These results serve as a foundation for the efficient production of PQ6 biomass that can be used as a food supplement for humans and aquaculture in the future.