Thraustochytrids are a group of unicellular marine heterotrophic protists,and have long been known for their biotechnological potentials in producing squalene,polyunsaturated fatty acids(PUFAs)and other bioactive prod...Thraustochytrids are a group of unicellular marine heterotrophic protists,and have long been known for their biotechnological potentials in producing squalene,polyunsaturated fatty acids(PUFAs)and other bioactive products.There are less than a hundred known strains from diverse marine habitats.Therefore,the discovery of new strains from natural environments is still one of the major limitations for fully exploring this interesting group of marine protists.At present,numerous attempts have been made to study thraustochytrids,mainly focusing on isolating new strains,analyzing the diversity in specific marine habitats,and increasing the yield of bioactive substances.There is a lack of a systematic study of the culturable diversity,and cultivation strategies.This paper reviews the distribution and diversity of culturable thraustochytrids from a range of marine environments,and describes in detail the most commonly used isolation methods and the control of culture parameters.Furthermore,the perspective approaches of isolation and cultivation for the discovery of new strains are discussed.Finally,the future directions of novel marine thraustochytrid research are proposed.The ultimate goal is to promote the awareness of biotechnological potentials of culturable thraustochytrid strains in industrial and biomedical applications.展开更多
Objective:To evaluate the antimicrobial activity of marine thraustochytrids extracted from different solvents.Methods:Crude extracts were derived from marine thraustochytrids,isolated from decaying mangrove leaf litte...Objective:To evaluate the antimicrobial activity of marine thraustochytrids extracted from different solvents.Methods:Crude extracts were derived from marine thraustochytrids,isolated from decaying mangrove leaf litter.The extracts were tested for antibacterial activity by using agar disc diffusion method against 10 clinical bacterial strains.The extracts were also analysed for presence of functional chemical groups by using Fourier transform infrared spectroscopy.Results:Thraustochytrid extracts exhibited potent antibacterial activity against both Gramnegative and-positive bacteria.The antibacterial activity was observed prominently in butanol extract,followed by petroleum ether,methanol and chloroform extracts.The antibacterial activity was maximum[(21.33±1.52)mm]against Staphylococcus aureus and minimum[(7.00±2.00)]mm against Klebsiella pneumonia and Salmonella typhi.Conclusions:Thraustochytrids isolated from decaying mangrove leaf litter are potential sources of antibacterial compounds against clinical pathogens,which are called for further investigation of thraustochytrids as natural antibiotics.展开更多
The objective of the studies in this paper was to expand on the published toxicological assessment of <i><span style="font-family:Verdana;">Aurantiochytrium</span></i> <i><sp...The objective of the studies in this paper was to expand on the published toxicological assessment of <i><span style="font-family:Verdana;">Aurantiochytrium</span></i> <i><span style="font-family:Verdana;">limacinum</span></i><span style="font-family:Verdana;"> (AURA) with further strain characterization and to investigate the potential for the biomass or extracted oil to have antimicrobial properties or undesirable substances. AURA is being investigated as a novel source of the omega-3 long-chain polyunsaturated fatty acid docosahexaenoic acid (DHA) for enriching foods of animal origin by means of feed supplementation. In the first studies, we provide</span><span style="font-family:Verdana;">d</span><span style="font-family:Verdana;"> the 18S rRNA identification of the novel marine isolated thraustochytrid, established the nutritional composition of AURA biomass for application as a food or feed ingredient including proximate analysis and fatty acid profiling, and confirmed the DHA production potential of the strain. We determined through minimum inhibitory concentration (MIC) analysis that the unextracted AURA biomass was safe, showing no antimicrobial influence and no evidence of any deleterious effects of this product or its extracts at concentrations up to 1% w/w on the reference human intestinal bacteria</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">tested. This would indicate that AURA should not stimulate selective pressure on the commensal microbiota and is therefore unlikely to aid development of antimicrobial resistance and the concomitant harm to humans and animals. Further analysis revealed that the AURA biomass produced through industrial heterotrophic fermentation was free from undesirables;toxic marine microalgal metabolites, heavy metals, pesticides, microbial contaminants, and mycotoxins. Including heterotrophically-grown AURA in food or feed, up to 1% w/w, is a safe and environmentally beneficial strategy for DHA supplementation.</span>展开更多
【目的】从深圳海域分离得到6株破囊壶菌,对其基本形态特征、生活史和油脂含量等进行研究,开发其应用潜力。【方法】使用松花粉垂钓法对破囊壶菌进行分离,通过18S r RNA基因测序的方法对破囊壶菌进行鉴定,用显微镜观察其基本形态特征,...【目的】从深圳海域分离得到6株破囊壶菌,对其基本形态特征、生活史和油脂含量等进行研究,开发其应用潜力。【方法】使用松花粉垂钓法对破囊壶菌进行分离,通过18S r RNA基因测序的方法对破囊壶菌进行鉴定,用显微镜观察其基本形态特征,通过使用尼罗红(Nile Red)染色法对油脂含量进行定性检测,并用GC-MS分析菌株的油脂含量和组成情况。【结果】18S r RNA基因鉴定其属于Aurantiochytrium sp.、Schizochytrium sp.和Thraustochytrium sp.三个属。破囊壶菌的脂肪酸主要成分为十六碳饱和脂肪酸和二十二碳六烯酸(DHA),其中Mn11和Mn15的饱和脂肪酸含量达到总脂肪酸含量的70%以上,Mn16和Sw7的DHA产量分别达到1.29 g/L和1.26 g/L。【结论】Mn11和Mn15菌株适合用于生物柴油的生产,Mn16和Sw7是DHA发酵生产的潜力菌株。展开更多
Thraustochytrids,rich in docosahexaenoic acid(DHA,C22:6u3),represent a potential source of dietary fatty acids.Yet,the effect of culture conditions on growth and fatty acid composition vary widely among different thra...Thraustochytrids,rich in docosahexaenoic acid(DHA,C22:6u3),represent a potential source of dietary fatty acids.Yet,the effect of culture conditions on growth and fatty acid composition vary widely among different thraustochytrid strains.Two different thraustochytrid strains,Schizochytrium sp.PKU#Mn4 and Thraustochytriidae sp.PKU#Mn16 were studied for their growth and DHA production characteristics under various culture conditions.Although they exhibited similar fatty acid profiles,PKU#Mn4 seemed a good candidate for industrial DHA fermentation while PKU#Mn16 displayed growth tolerance to a wide range of process conditions.Relative DHA content of 48.5%and 49.2%(relative to total fatty acids),respectively,were achieved on glycerol under their optimal flask culture conditions.Maximum DHA yield(Yp/x)of 21.0%and 18.9%and productivity of 27.6 mg/L-h and 31.9 mg/L-h were obtained,respectively,in 5-L bioreactor fermentation operated with optimal conditions and dual oxygen control strategy.A 3.4-and 2.8-fold improvement of DHA production(g/L),respectively,was achieved in this study.Overall,our study provides the potential of two thraustochytrid strains and their culture conditions for efficient production of DHA-rich oil.展开更多
基金This work was partially supported by National Science Foundation of China[91751115(GW)and 31670044(GW)]Natural Science Foundation of Hebei Province[D2019204215(QW)].The views expressed herein are those of the authors,and do not represent the views of the funding agencies or any of its subagencies.
文摘Thraustochytrids are a group of unicellular marine heterotrophic protists,and have long been known for their biotechnological potentials in producing squalene,polyunsaturated fatty acids(PUFAs)and other bioactive products.There are less than a hundred known strains from diverse marine habitats.Therefore,the discovery of new strains from natural environments is still one of the major limitations for fully exploring this interesting group of marine protists.At present,numerous attempts have been made to study thraustochytrids,mainly focusing on isolating new strains,analyzing the diversity in specific marine habitats,and increasing the yield of bioactive substances.There is a lack of a systematic study of the culturable diversity,and cultivation strategies.This paper reviews the distribution and diversity of culturable thraustochytrids from a range of marine environments,and describes in detail the most commonly used isolation methods and the control of culture parameters.Furthermore,the perspective approaches of isolation and cultivation for the discovery of new strains are discussed.Finally,the future directions of novel marine thraustochytrid research are proposed.The ultimate goal is to promote the awareness of biotechnological potentials of culturable thraustochytrid strains in industrial and biomedical applications.
基金Supported by University Grants Commission(CPEPA-G4(1)/1011/2012)and Ministry of Environment and Forests,Government of India.
文摘Objective:To evaluate the antimicrobial activity of marine thraustochytrids extracted from different solvents.Methods:Crude extracts were derived from marine thraustochytrids,isolated from decaying mangrove leaf litter.The extracts were tested for antibacterial activity by using agar disc diffusion method against 10 clinical bacterial strains.The extracts were also analysed for presence of functional chemical groups by using Fourier transform infrared spectroscopy.Results:Thraustochytrid extracts exhibited potent antibacterial activity against both Gramnegative and-positive bacteria.The antibacterial activity was observed prominently in butanol extract,followed by petroleum ether,methanol and chloroform extracts.The antibacterial activity was maximum[(21.33±1.52)mm]against Staphylococcus aureus and minimum[(7.00±2.00)]mm against Klebsiella pneumonia and Salmonella typhi.Conclusions:Thraustochytrids isolated from decaying mangrove leaf litter are potential sources of antibacterial compounds against clinical pathogens,which are called for further investigation of thraustochytrids as natural antibiotics.
文摘The objective of the studies in this paper was to expand on the published toxicological assessment of <i><span style="font-family:Verdana;">Aurantiochytrium</span></i> <i><span style="font-family:Verdana;">limacinum</span></i><span style="font-family:Verdana;"> (AURA) with further strain characterization and to investigate the potential for the biomass or extracted oil to have antimicrobial properties or undesirable substances. AURA is being investigated as a novel source of the omega-3 long-chain polyunsaturated fatty acid docosahexaenoic acid (DHA) for enriching foods of animal origin by means of feed supplementation. In the first studies, we provide</span><span style="font-family:Verdana;">d</span><span style="font-family:Verdana;"> the 18S rRNA identification of the novel marine isolated thraustochytrid, established the nutritional composition of AURA biomass for application as a food or feed ingredient including proximate analysis and fatty acid profiling, and confirmed the DHA production potential of the strain. We determined through minimum inhibitory concentration (MIC) analysis that the unextracted AURA biomass was safe, showing no antimicrobial influence and no evidence of any deleterious effects of this product or its extracts at concentrations up to 1% w/w on the reference human intestinal bacteria</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">tested. This would indicate that AURA should not stimulate selective pressure on the commensal microbiota and is therefore unlikely to aid development of antimicrobial resistance and the concomitant harm to humans and animals. Further analysis revealed that the AURA biomass produced through industrial heterotrophic fermentation was free from undesirables;toxic marine microalgal metabolites, heavy metals, pesticides, microbial contaminants, and mycotoxins. Including heterotrophically-grown AURA in food or feed, up to 1% w/w, is a safe and environmentally beneficial strategy for DHA supplementation.</span>
基金This work was partially supported by National Key R&D Program of China(2016YFA0601400)National Science Foundation of China(31670044,91751115,and 31602185).
文摘Thraustochytrids,rich in docosahexaenoic acid(DHA,C22:6u3),represent a potential source of dietary fatty acids.Yet,the effect of culture conditions on growth and fatty acid composition vary widely among different thraustochytrid strains.Two different thraustochytrid strains,Schizochytrium sp.PKU#Mn4 and Thraustochytriidae sp.PKU#Mn16 were studied for their growth and DHA production characteristics under various culture conditions.Although they exhibited similar fatty acid profiles,PKU#Mn4 seemed a good candidate for industrial DHA fermentation while PKU#Mn16 displayed growth tolerance to a wide range of process conditions.Relative DHA content of 48.5%and 49.2%(relative to total fatty acids),respectively,were achieved on glycerol under their optimal flask culture conditions.Maximum DHA yield(Yp/x)of 21.0%and 18.9%and productivity of 27.6 mg/L-h and 31.9 mg/L-h were obtained,respectively,in 5-L bioreactor fermentation operated with optimal conditions and dual oxygen control strategy.A 3.4-and 2.8-fold improvement of DHA production(g/L),respectively,was achieved in this study.Overall,our study provides the potential of two thraustochytrid strains and their culture conditions for efficient production of DHA-rich oil.
