• Journal of Microbiology and Biotechnology
• /
• v.26 no.3
• /
• pp.441-451
• /
• 2016

Squalene is a linear triterpene formed via the MVA or MEP biosynthetic pathway and is widely distributed in bacteria, fungi, algae, plants, and animals. Metabolically, squalene is used not only as a precursor in the synthesis of complex secondary metabolites such as sterols, hormones, and vitamins, but also as a carbon source in aerobic and anaerobic fermentation in microorganisms. Owing to the increasing roles of squalene as an antioxidant, anticancer, and anti-inflammatory agent, the demand for this chemical is highly urgent. As a result, with the exception of traditional methods of the isolation of squalene from animals (shark liver oil) and plants, biotechnological methods using microorganisms as producers have afforded increased yield and productivity, but a reduction in progress. In this paper, we first review the biosynthetic routes of squalene and its typical derivatives, particularly the squalene synthase route. Second, typical biotechnological methods for the enhanced production of squalene using microbial cell factories are summarized and classified. Finally, the outline and discussion of the novel trend in the production of squalene with several updated events to 2015 are presented.

• Advances in aircraft and spacecraft science
• /
• v.9 no.6
• /
• pp.537-551
• /
• 2022

The rapid decrease of fossil fuel resources and increase of environmental pollution caused by aviation industries have become a severe issue which leads to an increase in the greenhouse effect. The use of biofuel becomes an option to alleviate issues related to unrenewable resources. This study presents a computational simulation of the biofuel combustion characteristics of various alternative fuels in an annular combustion chamber designed for training aircraft. The biofuels used in this study are Sorghum Oil Methyl Ester (SOME), Spirulina Platensis Algae (SPA) and Camelina Hydrotreated Esters and Fatty Acids (CHEFA). Meanwhile, Jet-A is used as a baseline fuel. The fuel properties and combustion characteristics are being investigated and analysed. The results are presented in terms of temperature and pressure profiles in addition to the formation of NOx and soot generated from the combustion chamber. Results obtained show that CHEFA fuel is the most recommended biofuel among all four tested fuels as it is being found that it burns with 37.6% lower temperature, 15.2% lower pressure, 89.5% lower NOx emission and 8.1% lower soot emission compared with the baseline fuel in same combustion chamber geometry with same initial parameters.

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.06a
• /
• pp.250.2-250.2
• /
• 2010

빛과 공기 중의 이산화탄소를 고정화하여 생성되는 바이오매스(biomass)로부터 다양한 에너지 및 물질을 생산하는 연구는 석유고갈과 환경문제 해결의 한 방안으로서 활발히 진행되어 왔으며, 앞으로도 그 지속 가능성과 환경 친화성에 의해 바이오에너지 이용 및 보급은 꾸준한 증가세를 보일 것으로 전망된다. 바이오디젤, 바이오에탄올의 경우는 미국, 브라질, EU, 한국 등에서 상용화되어 사용되고 있으며 그 생산량이 계속적으로 증가하고 있다. 하지만, 바이오연료의 보급 증가는 식량 자원과의 충돌과 열대우림 파괴 등의 부작용을 일으키고 있다. 이러한 문제 해결의 일환으로 단위면적당 생산성이 대두, 유채보다 월등한 것으로 보고되는 미세조류에 대한 관심이 증가하고 있으며 우수 미세조류종 개발, 미세조류 고속배양 및 수확, 미세조류로부터 에너지 및 유용물질, 소재 생산에 대한 연구가 활발히 진행되고 있다. 본 연구에서는 미세조류로부터 바이오디젤 원료유를 생산하기 위해 Soxhlet을 이용한 추출 방법을 이용하였다. 추출되는 오일은 사용 용매의 극성에 따라 물성과 추출 효율에 차이가 큰 것으로 나타났다. 강한 극성의 용매일 경우, 엽록소와 단백질이 같이 추출되는 문제가 있으며 약한 극성 용매는 세포벽의 방해로 용매가 세포내부로 흡수되지 못하는 문제가 있다. 추출 효율이 높은 극성용매의 경우 불순물을 제거해야 고순도의 바이오디젤의 생산이 가능하고 비극성 용매는 추출 오일의 물성은 좋으나 수율이 매우 낮게 측정되었다. 이러한 동시추출을 방지함과 동시에 추출 효율을 높이기 위해 본 연구에서는 세포벽 파괴 후 용매추출하는 방법으로서 미세조류를 Microwave에 노출시켜 오일 추출율을 증가시키는 전처리 연구를 수행하였다. 전처리시, Microwave에 의한 열 발생은 미세조류를 탄화시키기 때문에 열매체로서 물을 혼합하여 탄화를 방지하고 세포벽 내외부의 가열효과로 세포벽을 파괴하고자 하였다. Microwave에 의한 에너지 손실을 줄이며 세포벽 파괴에 효과적인 수분혼합비를 조사하였으며 Microwave에 노출 후 잔류수분을 건조하고 효율적으로 용매를 접촉시키기 위해 분쇄를 수행하였다. 모든 전처리 반응을 거친 미세조류에서 약 2배 증가된 추출수율을 얻을 수 있었으며, SEM을 통해 전처리 미세조류와 미전처리 미세조류를 분석해본 결과 전처리 미세조류의 다공성이 증가함을 확인하였다. 또한, 90%의 메탄올에 미세조류를 녹여 엽록소 함유량을 측정한 결과, 전처리 미세조류의 엽록소가 미전처리 미세조류보다 약 7배가량 감소함을 확인할 수 있었다.

• Asian-Australasian Journal of Animal Sciences
• /
• v.22 no.9
• /
• pp.1341-1350
• /
• 2009

Dietary lipids are rapidly hydrolysed and biohydrogenated in the rumen resulting in meat and milk characterised by a high content of saturated fatty acids and low polyunsaturated fatty acids (PUFA), which contributes to increases in the risk of diseases including cardiovascular disease and cancer. There has been considerable interest in altering the fatty acid composition of ruminant products with the overall aim of improving the long-term health of consumers. Metabolism of dietary lipids in the rumen (lipolysis and biohydrogenation) is a major critical control point in determining the fatty acid composition of ruminant lipids. Our understanding of the pathways involved and metabolically important intermediates has advanced considerably in recent years. Advances in molecular microbial technology based on 16S rRNA genes have helped to further advance our knowledge of the key organisms responsible for ruminal lipid transformation. Attention has focused on ruminal biohydrogenation of lipids in forages, plant oils and oilseeds, fish oil, marine algae and fat supplements as important dietary strategies which impact on fatty acid composition of ruminant lipids. Forages, such as grass and legumes, are rich in omega-3 PUFA and are a useful natural strategy in improving nutritional value of ruminant products. Specifically this review targets two key areas in relation to forages: i) what is the fate of the lipid-rich plant chloroplast in the rumen and ii) the role of the enzyme polyphenol oxidase in red clover as a natural plant-based protection mechanism of dietary lipids in the rumen. The review also addresses major pathways and micro-organisms involved in lipolysis and biohydrogenation.

• Korean Chemical Engineering Research
• /
• v.56 no.4
• /
• pp.453-460
• /
• 2018

Owing to rising oil prices and anthropogenic global warming, focused attempts are being made toward production of industrially important compounds by using renewable biomass. In this context, algal biomass as third-generation biomass is important because it doesn't compatible with food resource, has high yield, and helps abate greenhouse gases. Here, we investigate whether Undaria has the highest sugar content, which would make it the most suitable biomass for lactic acid production among the four algal biomasses tested. For effective pretreatment of Undaria, the response surface methodology was used. The amount of solid loaded and catalyst concentration were related to the extraction rate of total sugar. Lactic acid was produced by pretreatment of Undaria by using four Lactobacilli, and L. alimentarius and L. brevis were found to be suitable for lactic acid production.

• Preventive Nutrition and Food Science
• /
• v.17 no.1
• /
• pp.1-7
• /
• 2012

The inhibitory effect of polyphenol extracts (Seapolynol$^{TM}$, SPN) of the marine brown algae Ecklonia cava and dieckol, a major component of SPN, on hyperlipidemia was investigated in ICR mice fed a high-fat diet (HFD) for five weeks. For analysis of the anti-hyperlipidemic effects of SPN and dieckol, these two agents were given orally on a daily basis to HFD-fed mice for four weeks, starting one week after the beginning of HFD feeding. Groups administered with SPN as well as dieckol showed lower body weight gains than the HFD only group. Administration of SPN and dieckol also resulted in a significant reduction of the level of total cholesterol (TCHO), triglyceride (TG), and low-density lipoprotein (LDL) cholesterol in the serum of HFD-fed mice. In Oil Red O staining using 3T3-L1 preadipocytes, it was shown that both SPN and dieckol markedly inhibited lipid accumulation of 3T3-L1 cells. Furthermore, SPN and dieckol (50 ${\mu}g$/mL) significantly inhibited 3-hydroxyl-methyl glutaryl coenzyme A (HMGCoA) reductase activity in vitro. Taken together, these results suggest that polyphenols of Ecklonia cava (SPN) and dieckol reduce body weight gain and fat accumulation in HFD-induced obese mice, and that their hypolipidemic effect is related to the inhibition of adipogenesis of adipocytes and HMGCoA reductase activity.

• Journal of the Korean GEO-environmental Society
• /
• v.11 no.8
• /
• pp.65-71
• /
• 2010

In this study, we have evaluated biodegradability of diesel-oxygenates including DBM and gasoline-oxygenates having similar physio-chemical properties using indigenous aerobic microorganisms from a diesel-contaminated soil. Toluene and Ethanol have shown higher biological activity and the first-order degradation rate constants ranged around $0.11{\sim}0.3day^{-1}$. However, MTBE, gasoline-oxygenate has shown as a limited substrate. Moreover, As increased initial concentrations of DBM and TGME, degradation rates of those were decreased relatively. As a strategy to evaluate biodegradability of DBM and TGME, reduction of diesel-oxygenates, $CO_2$ production and toxicity by algae were monitored. This results indicated possible mineralization of diesel-oxygenates, But we could predict that residual byproduct produced even though complete consumption of diesel-oxygenates were observed if algal toxicity variation considered. In conclusion, it is the first report that diesel-oxygenates including DBM could be biodegraded effectively by indigenous soil microorganisms and this result increased the possibility of bioremediation technology to apply into oil-contaminated sites.

• Journal of Korean Society on Water Environment
• /
• v.32 no.2
• /
• pp.197-204
• /
• 2016

The growth of the algae strain Chlorella vulgaris under mixotrophic conditions in the presence of saccharified acorn-starch (acorn-glucose) was evaluated with the objective of increasing biomass growth and triacylglycerols (TAGs) content. The results indicated that 81.3% of starch was converted to glucose in acorns. C.vulgaris algal strains grown with acorn-glucose produced higher biomass and TAGs content than with autotrophic growth. The highest biomass production and TAGs content with 3 g/L acorn-glucose were 12.44 g/L and 32.9%, respectively. Biomass production with 3 g/L acorn-glucose was 16.4 fold higher than under autotrophic growth condition. These findings suggested that 3 g/L acorn-glucose is economic and efficient for biomass production/productivity and TAGs content of microalgae. This study provides a feasible way to reduce the cost of bioenergy production from microalgae.

• Economic and Environmental Geology
• /
• v.38 no.3 s.172
• /
• pp.335-346
• /
• 2005

In this study, core sediments and pore water were analysed to identify the origin of organic matter and Bas in late Quaternary sediments from the northwestern Ulleung Basin of the East Sea. C/N and C/S ratios in the sediments show that the organic matter in the study area originated predominantly from marine algae. However, the results of Rock-Eval pyrolysis indicate that the organic matter has an origin of the land-plant (Type III), locating in the immature stage. These different results might be due to the heavy oxidizing of the organic matter during sinking down to the seafloor or after deposition in the sediments. Concentration of sulfate in the pore water decreases gradually with core depth, while concentration of $CH_4$ increases gradually with core depth. This indicates that sulfate reduction and methanogenesis occurred actively in the sediments. Also, it is likely that the compositions of $CH_4$ are characterized as a more biogenic origin, mostly caused by microbial activity, rather than a thermogenic one.

• Journal of Life Science
• /
• v.29 no.2
• /
• pp.209-214
• /
• 2019

Sargassum horneri (Turner) C. Agardh is a marine brown algae widely distributed in the North Pacific Ocean. It is known for its anti-inflammatory and anti-atopic effects. In this study, we determined the effects of ethanol extract of Sargassum horneri (Turner) C. Agardh (EESH) on anti-obesity activities in 3T3-L1 preadipocytes. Our results indicated that treatment with EESH decreased the differentiation of 3T3-L1 preadipocytes in a dose-dependent manner, as confirmed by a decrease in lipid droplet content observed by oil red O staining. The concentrations of cellular triglycerides were also reduced in 3T3-L1 cells after treatment with EESH. Triglyceride content was inhibited by 13%, 16%, and 23% after treatment with 250, 500, and $1,000{\mu}g/ml$ of EESH in 3T3-L1 cells, respectively. Western blotting analysis showed that EESH suppressed adipogenic transcription factor expression in a dose dependent manner. Specifically, it suppressed cytidine-cytidine-adinosine-adenosine-thymidine (CCAAT) /enhancer binding proteins $(C/EBP){\alpha}$, $C/EBP{\beta}$ and peroxisome proliferator-activated receptor $(PPAR){\gamma}$. This indicated that EESH could control the expression of adipogenic transcription factors and inhibit the differentiation of adipocytes. Taken together, these findings demonstrated that EESH showed anti-obesity effects and could have potential uses in the field of nutraceuticals.