Dataset Information

Heterologous mannitol-1-phosphate dehydrogenase gene over-expression in Parachlorella kessleri for enhanced microalgal biomass productivity.

ABSTRACT:

Background

Microalgae have tremendous potential in CO₂ sequestration, bioenergy, biofuels, wastewater treatment, and high-value metabolites production. However, large-scale production of microalgae is hampered due to photo-inhibition in outdoor cultivation. Mannitol, as an osmolyte, is known to relieve the stress produced under different abiotic stress conditions during the growth of a photosynthetic organism.

Results

In the present study, Mannitol-1-phosphate 5-dehydrogenase (Mt1D) was over-expressed to study the effect of mannitol over-production in Parachlorella kessleri under high-light induced stress. Over-expression of Mt1D led to 65% increased mannitol content in the transformed P. kessleri compared to that of wild type. Mannitol transformant demonstrated > 20-fold reduction in reactive oxygen species generation and 15% higher biomass productivity when grown in outdoor cultivation with high-light irradiance of 1200 μmol photons m^-2 s^-1.

Conclusions

The current study establishes that a higher mannitol concentration provides stress shielding and leads to better acclimatization of transgenic microalgae against high-light generated stress. It also led to reduced ROS generation and improved growth of microalga under study. Thus, overexpression of the Mt1D gene in microalgae can be a suitable strategy to combat high-light stress.

SUBMITTER: Rathod JP

PROVIDER: S-EPMC8885943 | biostudies-literature | 2022 Feb

REPOSITORIES: biostudies-literature

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Publications

Heterologous mannitol-1-phosphate dehydrogenase gene over-expression in Parachlorella kessleri for enhanced microalgal biomass productivity.

Rathod Jayant Pralhad JP Vira Chaitali C Lali Arvind M AM Prakash Gunjan G

Journal, genetic engineering & biotechnology 20220228 1

<h4>Background</h4>Microalgae have tremendous potential in CO<sub>2</sub> sequestration, bioenergy, biofuels, wastewater treatment, and high-value metabolites production. However, large-scale production of microalgae is hampered due to photo-inhibition in outdoor cultivation. Mannitol, as an osmolyte, is known to relieve the stress produced under different abiotic stress conditions during the growth of a photosynthetic organism.<h4>Results</h4>In the present study, Mannitol-1-phosphate 5-dehydro ...[more]

PMID: 35226194

Similar Datasets

Project description:BackgroundMicroalgae, with their high adaptability to various stress conditions and rapid growth, are considered excellent biomass resources for lipid production and biodiesel feedstocks. However, lipid yield and productivity of the natural strains are common bottlenecks in their large-scale use for lipid production, which can be overcome by evolving new strains using conventional and advanced mutagenic techniques. It is challenging to generate microalgae strains capable of high lipid synthesis through natural selection. As a result, random mutagenesis is currently considered a viable option in many scenarios. The objective of this study was to explore atmospheric and room temperature plasma (ARTP) as a random mutagenesis technique to obtain high lipid-accumulating mutants of a green microalga for improved biodiesel production.ResultsA green microalgal species was isolated from the Chinese Yellow Sea and identified as Parachlorella kessleri (OM758328). The isolated microalga was subsequently mutated by ARTP to obtain high lipid-accumulating mutants. Based on the growth rate and lipid content, 5 mutants (named M1, M2, M4, M5, and M8) were selected from 15 pre-selected mutants. These five mutants varied in their growth rate from 0.33 to 0.68 day-1, with the lipid content varying between 0.25 g/L in M2 to 0.30 g/L in M8 at 10th day of cultivation. Among the mutants, M8 showed the maximum biomass productivity (0.046 g/L/day) and lipid productivity (20.19 mg/L/day), which were 75% and 44% higher than the wild strain, respectively. The triglyceride (TAG) content of M8 was found to be 0.56 g/L at 16th day of cultivation, which was 1.77-fold higher than that of the wild strain. Furthermore, M8 had the highest saturated fatty acids (C16-18) with the lowermost polyunsaturated fatty acid content, which are favorable properties of a biodiesel feedstock according to international standards.ConclusionThe mutant strain of P. kessleri developed by the ARTP technique exhibited significant improvements in biomass productivity, lipid content, and biodiesel quality. Therefore, the biomass of this mutant microalga could be a potential feedstock for biodiesel production.

Project description:Attached culture allows high biomass productivity and is a promising biomass cultivating system because neither a huge facility area nor a large volume of culture medium are needed. This study investigates photosynthetic and transcriptomic behaviors in Parachlorella kessleri cells on a solid surface after their transfer from liquid culture to elucidate the physiological and gene-expression regulatory mechanisms that underlie their vigorous proliferation. The chlorophyll content shows a decrease at 12 h after the transfer; however, it has fully recovered at 24 h, suggesting temporary decreases in the amounts of light harvesting complexes. On PAM analysis, it is demonstrated that the effective quantum yield of PSII decreases at 0 h right after the transfer, followed by its recovery in the next 24 h. A similar changing pattern is observed for the photochemical quenching, with the PSII maximum quantum yield remaining at an almost unaltered level. Non-photochemical quenching was increased at both 0 h and 12 h after the transfer. These observations suggest that electron transfer downstream of PSII but not PSII itself is only temporarily damaged in solid-surface cells just after the transfer, with light energy in excess being dissipated as heat for PSII protection. It thus seems that the photosynthetic machinery acclimates to high-light and/or dehydration stresses through its temporal size-down and functional regulation that start right after the transfer. Meanwhile, transcriptomic analysis by RNA-Seq demonstrates temporary upregulation at 12 h after the transfer as to the expression levels of many genes for photosynthesis, amino acid synthesis, general stress response, and ribosomal subunit proteins. These findings suggest that cells transferred to a solid surface become stressed immediately after transfer but can recover their high photosynthetic activity through adaptation of photosynthetic machinery and metabolic flow as well as induction of general stress response mechanisms within 24 h.

Dataset Information

Heterologous mannitol-1-phosphate dehydrogenase gene over-expression in Parachlorella kessleri for enhanced microalgal biomass productivity.

Background

Results

Conclusions

Publications

Heterologous mannitol-1-phosphate dehydrogenase gene over-expression in Parachlorella kessleri for enhanced microalgal biomass productivity.

Similar Datasets

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