Comparison of lipid productivity of Parachlorella kessleri heavy-ion beam irradiation mutant PK4 in laboratory and 150-L mass bioreactor, identification and characterization of its genetic variation

Takeshita, Tsuyoshi; Ivanov, Ivan Nedyalkov; Oshima, Koichiro; Ishii, Kotaro; Kawamoto, Hiroki; Ota, Shuhei; Yamazaki, T.; Hirata, Aiko; Kazama, Yusuke; Abe, Tomoko; Hattori, Masahira; Bišová, Kateřina; Zachleder, Vilém; Kawano, Shigeyuki

doi:10.1016/j.algal.2018.09.005

Cited by 29 publications

(19 citation statements)

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“…Together with a massive 508-fold increase in starch, this made the biomass significantly enriched in starch and proteins. In general, starch (over)production can be attained either through increasing starch production by improving growth conditions (high light, high CO 2 concentration) [ 36 , 37 ] or by decreasing starch consumption—mainly by blocking cell reproduction as the biggest starch consumer under nutrient-limiting conditions [ 24 , 25 , 26 , 32 , 39 , 41 ]. Indeed, a blockage of cell division has emerged as an effective tool to (over)produce starch [ 79 ].…”

Section: Discussionmentioning

confidence: 99%

“…The chlorococcal alga Parachlorella kessleri (formerly Chlorella kessleri [ 19 ]) is a biotechnologically promising algal species [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ] that divides by multiple fission. Its cell cycle consists of multiple rounds of DNA replication that, after completion of the last one, are followed by successive nuclear divisions.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, a blockage of cell division processes as the primary starch consumers will lead to starch (over)accumulation. This has been established for different stress conditions, such as the application of inhibitors [ 36 ], nutrient starvation [ 24 , 25 , 32 , 36 ], high light intensity [ 32 ], the presence of a high concentration of CO 2 [ 37 ], or supra-optimal temperatures [ 18 ], and it should be explored biotechnologically [ 36 , 38 ]. If stress conditions are prolonged, starch reserves will gradually start to be replaced by neutral lipids—the secondary energy store of P. kessleri [ 23 , 24 , 32 , 39 ].…”

Section: Introductionmentioning

confidence: 99%

“…If stress conditions are prolonged, starch reserves will gradually start to be replaced by neutral lipids—the secondary energy store of P. kessleri [ 23 , 24 , 32 , 39 ]. Although neutral lipids under optimal growth conditions are maintained at a relatively low level, at 1–10% of dry matter (DM) [ 23 , 39 , 40 ], they can also (over)accumulate under stress conditions similar to those inducing starch accumulation, such as nitrogen, sulfur, or phosphorus depletion [ 24 , 26 , 32 , 39 , 41 ], dilution of all the nutrients in the medium [ 25 , 39 ] or salt stress [ 42 ]. The ability to (over)produce both starch and neutral lipids makes P. kessleri a useful model for applications in biotechnology.…”

Section: Introductionmentioning

confidence: 99%

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Supra-Optimal Temperature: An Efficient Approach for Overaccumulation of Starch in the Green Alga Parachlorella kessleri

Zachleder

Kselíková

Ivanov

et al. 2021

Cells

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Green algae are fast-growing microorganisms that are considered promising for the production of starch and neutral lipids, and the chlorococcal green alga Parachlorella kessleri is a favorable model, as it can produce both starch and neutral lipids. P. kessleri commonly divides into more than two daughter cells by a specific mechanism—multiple fission. Here, we used synchronized cultures of the alga to study the effects of supra-optimal temperature. Synchronized cultures were grown at optimal (30 °C) and supra-optimal (40 °C) temperatures and incident light intensities of 110 and 500 μmol photons m−2 s−1. The time course of cell reproduction (DNA replication, cellular division), growth (total RNA, protein, cell dry matter, cell size), and synthesis of energy reserves (net starch, neutral lipid) was studied. At 40 °C, cell reproduction was arrested, but growth and accumulation of energy reserves continued; this led to the production of giant cells enriched in protein, starch, and neutral lipids. Furthermore, we examined whether the increased temperature could alleviate the effects of deuterated water on Parachlorella kessleri growth and division; results show that supra-optimal temperature can be used in algal biotechnology for the production of protein, (deuterated) starch, and neutral lipids.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Supra-Optimal Temperature: An Efficient Approach for Overaccumulation of Starch in the Green Alga Parachlorella kessleri

Zachleder

Kselíková

Ivanov

et al. 2021

Cells

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“…This can be achieved by employing random mutagenesis and high-throughput screening techniques to identify genes that can contribute to improved lipid accumulation, mainly in the model microalgae Chlamydomonas reinhardtii [25][26][27]. Such random mutagenesis can be achieved through irradiation by UV [28,29], γ, and X-rays [30], as well as heavy ion beams [31], or by chemical mutagens, including ethyl methanesulfonate (EMS) [29,32], N-methyl-N′-nitro-Nnitrosoguanidine (MNNG) [33], and N-methyl-N-nitrosourea [34]. However, such random mutagenic techniques present difficulties in identification of the responsible gene(s); this can be solved by insertional mutagenesis [35,36].…”

Section: Introductionmentioning

confidence: 99%

Development and characterization of a Nannochloropsis mutant with simultaneously enhanced growth and lipid production

Ryu

Kang

Jeon

et al. 2020

Biotechnol Biofuels

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Background: The necessity to develop high lipid-producing microalgae is emphasized for the commercialization of microalgal biomass, which is environmentally friendly and sustainable. Nannochloropsis are one of the best industrial microalgae and have been widely studied for their lipids, including high-value polyunsaturated fatty acids (PUFAs). Many reports on the genetic and biological engineering of Nannochloropsis to improve their growth and lipid contents have been published. Results: We performed insertional mutagenesis in Nannochloropsis salina, and screened mutants with high lipid contents using fluorescence-activated cell sorting (FACS). We isolated a mutant, Mut68, which showed improved growth and a concomitant increase in lipid contents. Mut68 exhibited 53% faster growth rate and 34% higher fatty acid methyl ester (FAME) contents after incubation for 8 days, resulting in a 75% increase in FAME productivity compared to that in the wild type (WT). By sequencing the whole genome, we identified the disrupted gene in Mut68 that encoded trehalose-6-phosphate (T6P) synthase (TPS). TPS is composed of two domains: TPS domain and T6P phosphatase (TPP) domain, which catalyze the initial formation of T6P and dephosphorylation to trehalose, respectively. Mut68 was disrupted at the TPP domain in the C-terminal half, which was confirmed by metabolic analyses revealing a great reduction in the trehalose content in Mut68. Consistent with the unaffected N-terminal TPS domain, Mut68 showed moderate increase in T6P that is known for regulation of sugar metabolism, growth, and lipid biosynthesis. Interestingly, the metabolic analyses also revealed a significant increase in stress-related amino acids, including proline and glutamine, which may further contribute to the Mut68 phenotypes. Conclusion: We have successfully isolated an insertional mutant showing improved growth and lipid production. Moreover, we identified the disrupted gene encoding TPS. Consistent with the disrupted TPP domain, metabolic analyses revealed a moderate increase in T6P and greatly reduced trehalose. Herein, we provide an excellent proof of concept that the selection of insertional mutations via FACS can be employed for the isolation of mutants with

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Optimization of microalgal biomass and lipid productivities for bioenergy production using central composite design with desirability function

Hossain

Sultana

Hossain

et al. 2021

Intl J of Energy Research

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This study investigates the influences of light-dark cycles and NaNO 3 dose on Chlorella kessleri microalgal-specific growth rate (SGR), biomass productivity (P), and intracellular lipid productivity (LP) by using central composite design with desirability function. A single-objective optimization showed that the maximum SGR, P, and LP can be achieved as 0.487 day −1 , 58.718 g/L day −1 , and 14.252 mg/L day −1 , respectively. The corresponding optimized light-dark cycle and NaNO 3 loading were determined as 11.6/8.4 (h/h) and 15.54 g/L, 12/12 (h/h) and 16.23 g/L, and 12/12 (h/h) and 6.63 g/L, respectively. The multiresponse optimization showed that the highest SGR of 0.359 day −1 , biomass productivity of 50.663 g/L day −1 and LP of 14.114 mg/L day −1 can be accomplished at culture environments of 12/12 (h/h) light-dark cycles and 10.38 g/L NaNO 3 . These results suggest that the central composite design with desirability function-based technique is useful for design and operation of photobioreactors to produce lipid from microalgae. Analysis of variance was employed to explore the significance of the factors affecting microalgal growth as well as biomass and lipid productivities. The predicted optimized culture conditions were experimentally confirmed (error < 6%) indicating the process is robust and reliable.

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Comparison of lipid productivity of Parachlorella kessleri heavy-ion beam irradiation mutant PK4 in laboratory and 150-L mass bioreactor, identification and characterization of its genetic variation

Cited by 29 publications

References 50 publications

Supra-Optimal Temperature: An Efficient Approach for Overaccumulation of Starch in the Green Alga Parachlorella kessleri

Supra-Optimal Temperature: An Efficient Approach for Overaccumulation of Starch in the Green Alga Parachlorella kessleri

Development and characterization of a Nannochloropsis mutant with simultaneously enhanced growth and lipid production

Optimization of microalgal biomass and lipid productivities for bioenergy production using central composite design with desirability function

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