ABSTRACT
Selenium (Se) is an essential trace element for organisms. Se deficiency will cause diseases such as Keshan disease and Kashin-Beck in human being, and huge loss to animal husbandry. Currently available Se supplements have such problems as low Se content, poor bioavailability, and poor safety. Chlorella pyrenoidosa can produce bioavailable and safe organic Se under suitable conditions, which is thus a promising Se supplement. Therefore, in this study, we tried to improve the Se tolerance and accumulation of C. pyrenoidosa by directional adaptation. To be specific, we gradually increased the concentration of Na2SeO3 in medium to domesticate C. pyrenoidosa and optimized the adapting time and concentration gradient of Na2SeO3 during the adaptation. The results showed that the adapted C. pyrenoidosa was more tolerant to Se and had stronger Se enrichment ability. In 5 L fermenter, the adapted strains could tolerate 40 mg/L Na2SeO3 and the synthesis rate of organic Se was 175.6% higher. Then, Se addition method in the 5 L fermenter was optimized. The result demonstrated that addition of Na2SeO3 at 40 mg/L during heterotrophic culture achieved the final dry weight of C. pyrenoidosa cells at 106.4 g/L, content of organic Se at 1 227 mg/kg, and synthesis rate of organic Se at 1.36 mg/(L·h). Compared with the reported highest cell density of 75 g/L and the highest organic Se content of 560 mg/kg, the corresponding figures in this study were 41.9% and 119.1% higher, respectively. In conclusion, directional adaptation can remarkably improve the Se tolerance and enrichment of C. pyrenoidosa.
Subject(s)
Animals , Humans , Selenium/pharmacology , Chlorella , Heterotrophic ProcessesABSTRACT
The main functional ingredients of hot water extract of Chlorella pyrenoidosa (CPE) were investigated through a bioassay-guided fractionation based on free radical scavenging and macrophage proliferation effects. The main functional ingredients of CPE were polysaccharides (PS) that were isolated by high pressure extraction, Sevag method, ethanol precipitation and ultrafiltration separation. Crude polysaccharides were further separated and purified by ion exchange chromatography DEAE52 and size exclusion chromatography Sephadex G-100. The purified fractions were analyzed by gel permeation chromatography. Molecular weights of the purified fractions PS-1-4-2, PS-1-3-2 and PS-2-3-3 were 3.97×10⁴, 2.28×10⁴ and 4.1×10³ Da, respectively. Bioassay-guided fractionation results indicated that CPE could remove free radicals and promote Ana-1 cells proliferation, mainly due to its various components working together. The components of free radicals scavenging mainly concentrated in PS-1-3, PS-1-4, PS-2-3 and PS-2-4. The components of Ana-1 proliferation mainly concentrated in PS-1-3, PS-1-4 and PS-2-3. This study established the activity screening method of main functional component from CPE, and got three new functional ingredients. It can be used to guide the development of high value products, further promote the industrialization process of microalgae energy, and realize microalgae 'high value products, microalgae energy and microalgae carbon' integration of exemplary role.
ABSTRACT
This research was aimed at establishing the pilot-scale purification technology of lipopeptide from marine-derived Bacillus marinus. We studied lipopeptide surfactivity interferences on scale-up unit technologies including acid precipitation, methanol extraction, solvent precipitation, salting out, extraction, silica gel column chromatography and HZ806 macroporous absorption resin column chromatography. Then, the unit technologies were combined in a certain order, to remove the impurities gradually, and to gain purified lipopeptide finally, with high recovery rate throughout the whole process. The novel pilot-scale purification technology could effectively isolate and purify lipopeptide with 87.51% to 100% purity in hectograms from 1 ton of Bacillus marinus B-9987 fermentation broth with more than 81.73% recovery rate. The first practical hectogram production of highly purified lipopeptide derived from Bacillus marinus was achieved. With this new purification method, using complex media became possible in fermentation process to reduce the fermentation cost and scale-up the purification for lipopeptide production. For practicability and economy, foaming problem resulting from massive water evaporation was avoided in this technology.
ABSTRACT
Chlorella is nutritious and has been used as a functional food much earlier than the other microalgae. C. pyrenoidosa, the potential microalgae which is currently cultured and developed for the new strategic industry of biofuels production and biological CO2 fixation, is a new resource food announced by the Ministry of Health of the People's Republic of China late 2012. Accumulation of high value-added substances in C. pyrenoidosa during the cultivation for lipid makes it possible to reduce the costs for C. pyrenoidosa-based biofuels production. Among these potential substances, hot water extract of Chlorella (CE), commercially known as "Chlorella growth factor", is the unique one that makes Chlorella more precious than the other algae, and the market price of CE is high. It is believed that CE is effective in growth promotion and immunoregulation. However, there is no systematic analysis on the research status of CE and its bioactivity. The present report summarized recent research progress of CE and its bioactivity. Generally, besides the main effect on immunoregulation and tumor inhibition, CE was efficient in improving metabolic syndrome, scavenging for free radicals, protecting against ultraviolet damage, chelating heavy metals, and protecting liver and bowel. Several major challenges in CE research as well as its prospects were also analysed in the present report.
Subject(s)
Humans , Biofuels , Chlorella , Chemistry , Lipids , Chemistry , Plant Extracts , Chemistry , Pharmacology , WaterABSTRACT
Microalgae is a single-cell organism with the characteristics of high light energy utilization rate, fast growth rate, high-value bioactive components and high energy material content. Therefore, microalgae has broad application prospects in food, feed, bioenergy, carbon sequestration, wastewater treatment and other fields. In this article, the microalgae biotechnology development in recent years were fully consulted, through analysis from the literature and patent. The progress of microalgal biotechnology at home and abroad is compared and discussed. Furthermore, the project layout, important achievements and development bottlenecks of microalgae biotechnology in our country were also summarized. At last, future development directions of microalgae biotechnology were discussed.
Subject(s)
Bibliometrics , Biofuels , Biomass , Biotechnology , Microalgae , Metabolism , WastewaterABSTRACT
Photoautotrophic cultivation with heterotrophic cells as seeds (heterotrophic cells/photoautotrophic cultivation) is an effective way for the development of microalgal biofuel, but its development potential from the point of process optimization has not been investigated in literatures. To evaluate this, the optimizations of medium and culture conditions for Chlorella ellipsoidea were studied. In the heterotrophic stage, the biomass concentration reached 11.04 g/L with the optimized medium in flask, which were 28.0% higher than that with the original medium, and the biomass concentration reached 73.89 g/L in 5-L fermenter. In the photoautotrophic stage, the culture medium and conditions were studied in a 2-L column photobioreactor. The maximum biomass concentration, lipid content and lipid productivity reached 1.62 g/L, 36.34% and 6.1 mg/(L·h) under the optimal photoautotrophic conditions. The lipids were mainly composed of C16-C18 fatty acids, which were raw material suitable for biodiesel. After optimization, heterotrophic cells/photoautotrophic cultivation can significantly improve the capacity of biofuel production by Chlorella ellipsoidea, this method is also expected to be an efficient way for the cultivation of other microalgae that can grow heterotrophically.
Subject(s)
Biofuels , Biomass , Cell Culture Techniques , Chlorella , Metabolism , Culture Media , Fatty Acids , Heterotrophic Processes , Lipids , PhotobioreactorsABSTRACT
Objective To investigate the characteristic of etiology of chronic cough in Shenzhen.Methods The chronic cough etiology was analyzed in 136 cases with the guidance of cough diagnosis and treatment guidelines(2009 editions)published by Chinese Medical Association.The cough was the main or sole symptom,the duration was no less than 8 weeks and chest X-ray film was normal.Results The causes of chronic cough was confirmed in 125 patients and was not definitely diagnosed in 11 patients by inspection and treatment.Cough due to single cause was found in 104 patients(83.20%,104/125),due to compound causes was found in 21 patients(16.80%,21/125).The first 4 etiologies were cough variant asthma(CVA)with 57 patients(36.31%,57/157),upper airway cough syndrome(UACS)with 41 patients(26.11%,41/157),eosinophilic bronchitis(EB)with 17 patients(10.83%,17/157),occupational injury(including harmful,toxic substances inhalation,etc.)with 10 patients(6.37%,10/157).Conclusions The most common cause of chronic cough in Shenzhen is CVA,UACS,EB.Due to the developed industrialization,there is a lack of understanding the cough course of inhaling more harmful and toxic gases and substances in the manufacturing process.So this should be paid more attention.
ABSTRACT
With the dwindling of fossil fuels supply and the urgent need for the development of low-carbon economy, microalgae bioenergy, both renewable and environmentally friendly, has become one of the worldwide focuses. Given its benefit to the security of national energy supply, microalgae energy is particularly significant for China, with more than 50% crude oil imported and limited arable land for grain and edible oil production. In this article, both the advantages of microalgae bioenergy and the challenges of its development are addressed, which involves fundamental research and technology development as well as commercial production. Furthermore, strategies are proposed for China's microalgae bioenergy development, and its prospects are projected.
Subject(s)
Biofuels , Biotechnology , Methods , Conservation of Energy Resources , Methods , Microalgae , MetabolismABSTRACT
0.05,respectively).Plasma Mg2+,intracellular Mg2+,the beta 2-AR mRNA and protein in lung tissue in group C at 21st d and 34th d were significantly higher than those in group A at 21st d and 34th d 21st d:(0.84?0.09)mmol/L vs 0.57?0.10)mmol/L,(2.39?0.14)mmol/L vs(2.11?0.08)mmol/L,(0.75?0.09)pmol/g vs(0.59?0.06)pmol/g,(88.50?8.50)pmol/g vs(60.10?7.70)pmol/g,P