Limits to biomass productivity during fed-batch cultivation of Laminaria saccharina female gametophyte cells in a stirre
- PDF / 672,701 Bytes
- 9 Pages / 595.276 x 790.866 pts Page_size
- 18 Downloads / 124 Views
Limits to biomass productivity during fed-batch cultivation of Laminaria saccharina female gametophyte cells in a stirred-tank photobioreactor Sundar Ramanan 1 & Gregory L. Rorrer 1 Received: 24 September 2020 / Revised and accepted: 5 November 2020 # Springer Nature B.V. 2020
Abstract This study compared the growth of Laminaria saccharina female gametophyte filamentous cell suspension cultures in a stirredtank photobioreactor under batch and fed-batch nutrient addition modes over a 48-day cultivation period. Cultures were grown on GP2 artificial seawater medium (0.75 mM nitrate, N:P = 16:1) at pH 8.3 without iron or copper. Total equivalent nutrient loadings ranged from 0.5X to 9.1X GP2 for batch cultivation and 1.3X to 10.4X GP2 for fed-batch cultivation at delivery rates of 0.0067– 0.16 mmol N L−1 day−1 based on nitrate. The multicellular, L. saccharina filamentous clumps were dispersed to nominal size of 100 μm by mechanical blending (~ 16,000 rpm, 5 s) prior to inoculation. Fed-batch addition of all nutrients enhanced biomass productivity by a factor of two over a batch cultivation process at equivalent total nutrient loadings in a stirred-tank photobioreactor. Peak productivity through fed-batch cultivation was 57 mg DCW L−1 day−1, and average final biomass densities exceeded 1800 mg DCW L−1, vs. 30 mg DCW L−1 day−1 and 800–900 mg DCW L−1 for batch cultivation. However, there was a limit to biomass productivity enhancement at cumulative nutrient loadings greater than 3X GP2 that was not the result of insufficient CO2 or light delivery. It is suggested that the formation of large, multicellular clumps approaching 1-mm diameter during stirred-tank cultivation may have ultimately reduced biomass productivity during fed-batch cultivation under nutrientreplete conditions. Therefore, future bioreactor processing strategies might consider mechanical blending to disperse the filament clumps during the cultivation process. Keywords Gametophyte . Laminaria . Phaeophyceae . Nutrient . Photobioreactor
Introduction Brown macroalgae, particularly kelp within the order Laminariales, are a commercially important source of food and hydrocolloids, with global production through aquaculture exceeding 8 million tonnes per year (FAO 2018). They are also an emerging source of nutraceuticals, cosmetics, bioactive compounds, and biofuels. Kelps possess a heteromorphic life history with a microscopic haploid gametophyte phase and a macroscopic diploid sporophyte phase. The development of sustainable aquaculture systems for kelp production requires continued development of tools and technologies for hatchery operations, particularly gametophytes (Charrier et al. 2017) and strategies to enable their mass cultivation (Zhang et al. 2008). * Gregory L. Rorrer [email protected] 1
School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA
Bioreactor cultivation of the photosynthetic microscopic kelp gametophyte life phase in liquid suspension culture provides a platform
Data Loading...
