Influence of mixotrophic growth on rhythmic oscillations in expression of metabolic pathways in diazotrophic cyanobacterium Cyanothece sp. ATCC 51142.
This study investigates the influence of mixotrophy on physiology and metabolism by analysis of global gene expression in unicellular diazotrophic cyanobacterium Cyanothece sp. ATCC 51142 (henceforth Cyanothece 51142). It was found that Cyanothece 51142 continues to oscillate between photosynthesis and respiration in continuous light under mixotrophy with cycle time of ∼ 13 h. Mixotrophy is marked by an extended respiratory phase compared with photoautotrophy. It can be argued that glycerol provides supplementary energy for nitrogen fixation, which is derived primarily from the glycogen reserves during photoautotrophy. The genes of NDH complex, cytochrome c oxidase and ATP synthase are significantly overexpressed in mixotrophy during the day compared to autotrophy with synchronous expression of the bidirectional hydrogenase genes possibly to maintain redox balance. However, nitrogenase complex remains exclusive to nighttime metabolism concomitantly with uptake hydrogenase. This study throws light on interrelations between metabolic pathways with implications in design of hydrogen producer strains.
Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
S
S
Krishnakumar
Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
Sandeep B
SB
Gaudana
Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
Madhuri G
MG
Digmurti
Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
Ganesh A
GA
Viswanathan
School of Information Technology, Federation University Australia, Gippsland Campus, VIC 3841, Australia.
Madhu
M
Chetty
Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India; Wadhwani Research Center for Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India; DBT-Pan IIT Center for Bioenergy, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India. Electronic address: wangikar@iitb.ac.in.
Pramod P
PP
Wangikar
D052818:Autotrophic Processes; D001709:Biotechnology / Q000379:methods; D002245:Carbon Dioxide / Q000737:chemistry; D016000:Cluster Analysis; D003470:Culture Media; D000458:Cyanobacteria / Q000378:metabolism*; D046889:Cyanothece / Q000378:metabolism*; D004579:Electron Transport; D020869:Gene Expression Profiling; D005990:Glycerol / Q000737:chemistry; D006003:Glycogen / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D053858:Metabolic Networks and Pathways; D009584:Nitrogen / Q000737:chemistry; D009586:Nitrogen Fixation; D009591:Nitrogenase / Q000737:chemistry; D020411:Oligonucleotide Array Sequence Analysis; D009991:Oscillometry; D058433:Photobioreactors; D055668:Photochemical Processes; D010788:Photosynthesis; D016897:Respiratory Burst; D059467:Transcriptome
D003470:Culture Media; D002245:Carbon Dioxide; D006859:Hydrogen; D006003:Glycogen; D009591:Nitrogenase; D009584:Nitrogen; D005990:Glycerol
Cyanobacteria; Hydrogen production; Metabolic oscillations; Nitrogen fixation; Transcriptomic analysis