Co-cultivation of siderophore-producing bacteria Idiomarina loihiensis RS14 with Chlorella variabilis ATCC 12198, evaluation of micro-algal growth, lipid, and protein content under iron starvation
Co-cultivation systems offer the potential to commercialize microalgae biomass. The key purpose of the study was to understand the relationship between siderophore-producing bacterium Idiomarina loihiensis RS14 and Chlorella variabilis ATCC 12198 strain for Chlorella growth enhancement. After observing growth enhancement in C. variabilis by adding metal chelator deferroxamine mesylate (siderophore standard) and purified siderophore from I. loihiensis (1 mg mL−1), a co-cultivation system was designed where axenic microalgae and co-cultured (microalgae + bacteria) aliquots were grown in (1:9, 9:1, 1:1) volumetric inoculum ratio (mL) under iron-sufficient and iron-deficient conditions. The co-culture volumetric ratio 1:1 (microalgae/bacteria) showed bleaching of microalgae and 1:9 showed less biomass (310 mg L−1) comparatively with 9:1 that increased 35% of biomass, i.e., 650 mg L−1 (axenic) to 1000 mg L−1 (co-cultured) in iron-deficient media. The inoculum ratios were optimized in 100 mL shake flask and 9:1 ratio was further scaled up with the similar conditions, and the co-culture showed 20% increase in biomass, i.e., 285.6 mg L−1 (axenic) to 356 mg L−1 (co-cultured). The co-cultured biomass contains 19.70% lipid content compared with axenic algae, i.e., 18.41% which shows 7% of increase in co-culture. Protein content increased to 30% in co-culture microalgae compared with axenic microalgae. Scanning electron microscope images show crumpled surface of Chlorella cells in co-cultured compared with its axenic cells. This finding is of interest for biofuel production from microalgae, often attained through nutrient-starvation processes leading to oil accumulation.
KeywordsCo-cultivation Micro-algal growth enhancement Iron starvation Siderophore Lipid
We are thankful to Ms. Khushbu Bhayani, Dr. Kaumeel Chokshi, and Dr. Sourish Bhattacharya for their timely help. We are also thankful to Mr. Jayesh Chaudhary for SEM analysis.
CSIR-CSMCRI Registration Number PRIS 098/2017 has been assigned to the manuscript. RS acknowledges DST for her INSPIRE funding support. PB acknowledges CSIR-SRF for the funding support. RS, PB, and RKS acknowledge AcSIR for their Ph.D. enrolment.
- Akbarnezhad M, Mehrgan MS, Kamali A, Baboli MJ (2016) Bioaccumulation of Fe+2 and its effects on growth and pigment content of Spirulina (Arthrospira platensis). AACL Bioflux 9:227–238Google Scholar
- Andersen RA (ed) (2005) Algal Culturing Techniques. Academic Press, West Boothbay HarborGoogle Scholar
- Avendaño-Herrera R, Riquelmes C, Silva F, Avendañod M, Irgang R (2003) Optimization of settlement of larval Argopecten purpuratus using natural diatom biofilms. J Shellfish Res 22:393–399Google Scholar
- Bendale MS, Chaudhari BL, Chincholkar SB (2010) Influence of environmental factors on siderophore production by Streptomyces fulvissimus ATCC 27431. Curr Trends Biotechnol Pharm 3:362–371Google Scholar
- Fujita MJ, Nakano K, Sakai R (2013) Bisucaberin B, a linear hydroxamate class siderophore from the marine bacterium Tenacibaculum mesophilum. Molecules 184:3917–26Google Scholar
- Geng H, Belas R (2010) Molecular mechanisms underlying Roseobacter–phytoplankton symbioses. Curr Opin Biotechnol 21:332–338Google Scholar
- Kean MA, Delgado EB, Mensink BP, Bugter MH (2015) Iron chelating agents and their effects on the growth of Pseudokirchneriella subcapitata, Chlorella vulgaris, Phaeodactylum tricornutum and Spirulina platensis in comparison to Fe-EDTA. J Algal Biomass Util 6:56–73Google Scholar
- Keshtacher-Liebso E, Hadar Y, Chen Y (1995) Oligotrophic bacteria enhance algal growth under iron-deficient conditions. Appl Environ Microbiol 616:2439–2441Google Scholar
- Lichtenthaler HK (1987) Chlorophylls and carotenoids: pigments of photosynthetic biomembranes. Methods Enzymol 148:350–382Google Scholar
- Smriga S, Fernandez VI, Mitchell JG, Stocker R (2016) Chemotaxis toward phytoplankton drives organic matter partitioning among marine bacteria. Proc Natl Acad Sci-Biol:1131576–1131581Google Scholar
- Sunda WG, Price NM, Morel FM (2005) Trace metal ion buffers and their use in culture studies. In: Andersen RA (ed) Algal culturing techniques. Academic Press, London, pp 35–63Google Scholar
- Vraspir JM, Holt PD, Butler A (2011) Identification of new members within suites of amphiphilic marine siderophores. Biometals 241:85–92Google Scholar