Enhancement of lipid productivity by adopting multi-stage continuous cultivation strategy in Nannochloropsis gaditana

Sung, Min-Gyu; Lee, Bongsoo; Kim, Chul Woong; Nam, Kibok; Chang, Yong Keun

doi:10.1016/j.biortech.2016.12.100

Cited by 24 publications

(11 citation statements)

References 34 publications

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“…The nutrients required by the cells rapidly returned to the initial status. A new continuous fed‐batch cultivation with starters from the former stage and fresh culture was rebuilt with the low contaminant unlike discontinuous method (Sung, Lee, Kim, Nam, & Chang, ). At this point, the cell concentration or the amount of the inoculum reached 0.606 × 10 8 , 0.775 × 10 8 , and 1.320 × 10 8 cells/ml.…”

Section: Resultsmentioning

confidence: 99%

A novel strategy and kinetics analysis of half‐fractional high cell density fed‐batch cultivation of Zygosaccharomyces rouxii

Zhou

Yang

et al. 2018

Food Science & Nutrition

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Zygosaccharomyces rouxii is an important microorganism for aroma production in traditional fermented foods. Using Z. rouxii as the original strain, the batch was split after glucose depletion in the culture medium. Half of the volume of the culture medium was released, and fresh culture medium was fed in. The exponential culture kinetics and the formula for the half‐fractional fed‐batch cultivations were determined to achieve a new strategy for high cell density culturing of Z. rouxii. Based on a full cultivation, three half‐fractional fed‐batch cultivations were performed after every 10 hr of culture. The specific growth rates of Z. rouxii at the different stages were in the order μX0>μX1>μX2>μX3 (0.525 to 0.229 hr−1). The glucose substrate consumption rates gradually decreased following the order μS0>μS1>μS2>μS3 (−1.165 to −0.722, g/g). The equation models for cell growth and glucose substrate consumption showed typical exponential behavior. The total cell yield was 1.78‐fold higher than the yield from a full cultivation, and this continuous subculture strategy also indicated a higher efficiency than traditional full cultivation. A new strategy for highly efficient culturing of Z. rouxii was achieved in a pilot scale. A foundation with data support for the production and application of Z. rouxii was developed.

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Section: Resultsmentioning

confidence: 99%

A novel strategy and kinetics analysis of half‐fractional high cell density fed‐batch cultivation of Zygosaccharomyces rouxii

Zhou

Yang

et al. 2018

Food Science & Nutrition

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“…Even so, the dye-based manner of stimulating lipid production could still have potential for utilization in continuous mode of cultivation, such as a system based on a continuous multi-stage process [30]. …”

Section: Discussionmentioning

confidence: 99%

Wavelength shift strategy to enhance lipid productivity of Nannochloropsis gaditana

Sung

Han

Lee

et al. 2018

Biotechnol Biofuels

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BackgroundMicroalgae, being a phototroph, grow in the presence of light, and utilizing photons in narrow and specific range of wavelengths. There have been numerous attempts to take advantage of this trait of wavelength-dependent growth for the purpose of increasing biomass productivity. One potential option involves wavelength conversion of sunlight. In the present study, three fluorescent dyes with blue, red, and green emission spectra were employed with the aim of improving sunlight utilization efficiency and thus enhancing biomass and lipid productivity of Nannochloropsis gaditana.ResultsWhen DPA and R101 were used to enrich blue and red spectra, biomass productivity of Nannochloropsis gaditana was increased by 35.1 and 40.3%, respectively. The maximum quantum yield values were higher than 0.6 at the early stage of growth for the cultures grown under DPA- and R101-modified solar radiation. Chlorophyll a content was also 57.0 and 32.3% higher than the control at the early growth stage under DPA- and R101-modified solar radiation, respectively. This stimulation of photosynthetic activity at the early growth stage correlated well with rapid growth under DPA- and R101-modified light during the first 4 days of cultivation. Lipid productivity consequently increased by 26.9 (DPA) and 39.4% (R101) after 10 days of cultivation. An immediate effect on lipid induction was observed in cultures under modified light, which exhibited 19.1% improvement in lipid content at the cost of some degree of impaired growth.ConclusionFluorescent dyes with the capability of enriching wavelengths of light favored by the algal photosystem could indeed be an effective means of promoting growth of Nannochloropsis gaditana. This strategy would be particularly powerful for mass cultivation where sunlight is the only economically viable option for illumination.Electronic supplementary materialThe online version of this article (10.1186/s13068-018-1067-2) contains supplementary material, which is available to authorized users.

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“…A flat‐panel PBR was used for the continuous cultivation of WT and transformant cells (Sung, Lee, Kim, Nam, & Chang, ). This PBR has dimensions of 35 mm × 240 mm × 310, and 2.5 l working volume.…”

Section: Methodsmentioning

confidence: 99%

“…A flat-panel PBR was used for the continuous cultivation of WT and transformant cells (Sung, Lee, Kim, Nam, & Chang, 2017).…”

Section: Methodsmentioning

confidence: 99%

Increased biomass and lipid production by continuous cultivation of Nannochloropsis salina transformant overexpressing a bHLH transcription factor

Kang

Kim

Sung

et al. 2019

Biotech & Bioengineering

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Microalgae are promising feedstocks for sustainable and eco‐friendly production of biomaterials, which can be improved by genetic engineering. It is also necessary to optimize the processes to produce biomaterials from engineered microalgae. We previously reported that genetic improvements of an industrial microalga Nannochloropsis salina by overexpressing a basic helix‐loop‐helix transcription factor (NsbHLH2). These transformants showed an improved growth and lipid production particularly during the early phase of culture under batch culture. However, they had faster uptake of nutrients, resulting in earlier starvation and reduced growth during the later stages. We attempted to optimize the growth and lipid production by growing one of the transformants in continuous culture with variable dilution rate and feed nitrogen concentration. Relative to wild‐type, NsbHLH2 transformant consumed more nitrate at a high dilution rate (0.5 day −1 ), and had greater biomass production. Subsequently, nitrogen limitation at continuous cultivation led to an increased fatty acid methyl ester production by 83.6 mg l −1 day −1 . To elucidate genetic mechanisms, we identified the genes containing E‐boxes, known as binding sites for bHLH transcription factors. Among these, we selected 18 genes involved in the growth and lipid metabolism, and revealed their positive contribution to the phenotypes via quantitative real‐time polymerase chain reaction. These results provide proof‐of‐concept that NsbHLH2 can be used to produce biomass and lipids.

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Enhancement of lipid productivity by adopting multi-stage continuous cultivation strategy in Nannochloropsis gaditana

Cited by 24 publications

References 34 publications

A novel strategy and kinetics analysis of half‐fractional high cell density fed‐batch cultivation of Zygosaccharomyces rouxii

A novel strategy and kinetics analysis of half‐fractional high cell density fed‐batch cultivation of Zygosaccharomyces rouxii

Wavelength shift strategy to enhance lipid productivity of Nannochloropsis gaditana

Increased biomass and lipid production by continuous cultivation of Nannochloropsis salina transformant overexpressing a bHLH transcription factor

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