Substrate degradation, biodiesel production, and microbial community of two electro-fermentation systems on treating oleaginous microalgae Nannochloropsis sp

Biodiesel is an eco-friendly, renewable, and potential liquid biofuel mitigating greenhouse gas emissions. Biodiesel has been produced initially from vegetable oils, non-edible oils, and waste oils. However, these feedstocks have several disadvantages such as requirement of land and labor and remain expensive. Similarly, in reference to waste oils, the feedstock content is succinct in supply and unable to meet the demand. Recent studies demonstrated utilization of lignocellulosic substrates for biodiesel production using oleaginous microorganisms. These microbes accumulate higher lipid content under stress conditions, whose lipid composition is similar to vegetable oils. In this paper, feedstocks used for biodiesel production such as vegetable oils, non-edible oils, oleaginous microalgae, fungi, yeast, and bacteria have been illustrated. Thereafter, steps enumerated in biodiesel production from lignocellulosic substrates through pretreatment, saccharification and oleaginous microbe-mediated fermentation, lipid extraction, transesterification, and purification of biodiesel are discussed. Besides, the importance of metabolic engineering in ensuring biofuels and biorefinery and a brief note on integration of liquid biofuels have been included that have significant importance in terms of circular economy aspects.

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Nutrient deficiency and an algicidal bacterium improved the lipid profiles of a novel promising oleaginous dinoflagellate, Prorocentrum donghaiense, for biodiesel production

Applied and Environmental Microbiology ◽

10.1128/aem.01159-21 ◽

2021 ◽

Author(s):

Jiali Gui ◽

Shuangshuang Chen ◽

Guiying Luo ◽

Zixiang Wu ◽

Yongxian Fan ◽

...

Keyword(s):

Lipid Content ◽

Energy Savings ◽

Lipid Production ◽

Nutrient Deficiency ◽

Extraction Process ◽

Oil Extraction ◽

Biodiesel Production ◽

Prorocentrum Donghaiense ◽

Algicidal Bacterium ◽

Oleaginous Microalgae

The lipid production potential of 8 microalgae species was investigated. Among these eight species, the best strain was a dominant bloom-causing dinoflagellate, Prorocentrum donghaiense ; this species had a lipid content of 49.32±1.99% and exhibited a lipid productivity of 95.47±0.99 mg L −1 d −1 , which was 2-fold higher than the corresponding values obtained for the oleaginous microalgae Nannochloropsis gaditana and Phaeodactylum tricornutum . P. donghaiense, which is enriched in C16:0 and C22:6, is appropriate for commercial DHA production. Nitrogen or phosphorus stress markedly induced lipid accumulation to levels surpassing 75% of the dry weight, increased the C18:0 and C17:1 contents, and decreased the C18:5 and C22:6 contents, and these effects resulted in decreases in the unsaturated fatty-acid levels and changes in the lipid properties of P. donghaiense such that the species met the biodiesel specification standards. Compared with the results obtained under N-deficient conditions, the enhancement in the activity of alkaline phosphatase of P. donghaiense observed under P-deficient conditions could partly alleviate the adverse effects on the photosynthetic system exerted by P deficiency to induce the production of more carbohydrates for lipogenesis. The supernatant of the algicidal bacterium Paracoccus sp. Y42 culture lysed P. donghaiense without decreasing its lipid content, which resulted in facilitation of the downstream oil extraction process and energy savings through the lysis of algal cells. The Y42 supernatant treatment improved the lipid profiles of algal cells by increasing their C16:0, C18:0 and C18:1 contents and decreasing their C18:5 and C22:6 contents, which is favourable for biodiesel production. IMPORTANCE This study demonstrates the high potential of P. donghaiense , a dominant bloom-causing dinoflagellate, for lipid production. Compared with previously studied oleaginous microalgae, P. donghaiense exhibit greater potential for practical application due to its higher biomass and lipid contents. Nutrient deficiency and the algicidal bacterium Paracoccus sp. Y42 could improve the suitability of the lipid profile of P. donghaiense for biodiesel production. Furthermore, Paracoccus sp. Y42 effectively lyse algal cells, which facilitates the downstream oil extraction process for biodiesel production and results in energy savings through the lysing of algal cells. This study provides a more promising candidate for the production of DHA for human nutritional products and of microalgal biofuel, as well as a more cost-effective method for breaking algal cells. The high lipid productivity of P. donghaiense and algal cell lysis by algicidal bacteria contribute to reductions in the production cost of microalgal oil.

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Bioremediation of domestic and industrial wastewaters integrated with enhanced biodiesel production using novel oleaginous microalgae

Environmental Science and Pollution Research ◽

10.1007/s11356-016-7320-y ◽

2016 ◽

Vol 23 (20) ◽

pp. 20997-21007 ◽

Cited By ~ 22

Author(s):

Neha Arora ◽

Alok Patel ◽

Km Sartaj ◽

Parul A. Pruthi ◽

Vikas Pruthi

Keyword(s):

Biodiesel Production ◽

Industrial Wastewaters ◽

Oleaginous Microalgae

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Enhanced lipid and biodiesel production from glucose-fed activated sludge: Kinetics and microbial community analysis

AIChE Journal ◽

10.1002/aic.12655 ◽

2011 ◽

Vol 58 (4) ◽

pp. 1279-1290 ◽

Cited By ~ 38

Author(s):

Andro H. Mondala ◽

Rafael Hernandez ◽

Todd French ◽

Linda McFarland ◽

Jorge W. Santo Domingo ◽

...

Keyword(s):

Microbial Community ◽

Activated Sludge ◽

Community Analysis ◽

Biodiesel Production ◽

Microbial Community Analysis

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Integration process of biodiesel production from filamentous oleaginous microalgae Tribonema minus

Bioresource Technology ◽

10.1016/j.biortech.2013.05.058 ◽

2013 ◽

Vol 142 ◽

pp. 39-44 ◽

Cited By ~ 46

Author(s):

Hui Wang ◽

Lili Gao ◽

Lin Chen ◽

Fajin Guo ◽

Tianzhong Liu

Keyword(s):

Biodiesel Production ◽

Integration Process ◽

Oleaginous Microalgae ◽

Tribonema Minus

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Molecular Mechanism of Lipid Accumulation and Metabolism of Oleaginous Chlorococcum sphacosum GD from Soil under Salt Stress

International Journal of Molecular Sciences ◽

10.3390/ijms22031304 ◽

2021 ◽

Vol 22 (3) ◽

pp. 1304

Author(s):

Hang Su ◽

Jia Feng ◽

Junping Lv ◽

Qi Liu ◽

Fangru Nan ◽

...

Keyword(s):

Salt Stress ◽

Fatty Acid ◽

Lipid Content ◽

Salt Concentration ◽

Lipid Accumulation ◽

Transcriptome Sequencing ◽

High Throughput Sequencing ◽

Lipid Production ◽

Biodiesel Production ◽

Oleaginous Microalgae

The oleaginous microalgae species Chlorococcum sphacosum GD is a promising feedstock for biodiesel production from soil. However, its metabolic mechanism of lipid production remains unclear. In this study, the lipid accumulation and metabolism mechanisms of Chlorococcum sphacosum GD were analyzed under salt stress based on transcriptome sequencing. The biomass and lipid content of the alga strain were determined under different NaCl concentrations, and total RNA from fresh cells were isolated and sequenced by HiSeq 2000 high throughput sequencing technology. As the salt concentration increased in culture medium, the algal lipid content increased but the biomass decreased. Following transcriptome sequencing by assembly and splicing, 24,128 unigenes were annotated, with read lengths mostly distributed in the 200–300 bp interval. Statistically significant differentially expressed unigenes were observed in different experimental groups, with 2051 up-regulated genes and 1835 down-regulated genes. The lipid metabolism pathway analysis showed that, under salt stress, gene-related fatty acid biosynthesis (ACCase, KASII, KAR, HAD, FATA) was significantly up-regulated, but some gene-related fatty acid degradation was significantly down-regulated. The comprehensive results showed that salt concentration can affect the lipid accumulation and metabolism of C. sphacosum GD, and the lipid accumulation is closely related to the fatty acid synthesis pathway.

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