Quantification of Tetradesmus obliquus (Chlorophyceae) cell size and lipid content heterogeneity at single‐cell level

Abstract

Much of our current knowledge of microbial growth is obtained from studies at a population level. Driven by the realization that processes that operate within a population might influence a population's behavior, we sought to better understand Tetradesmus obliquus (formerly Scenedesmus obliquus) physiology at the cellular level. In this work, an accurate pretreatment method to quantitatively obtain single cells of T. obliquus, a coenobia-forming alga, is described. These single cells were examined by flow cytometry for triacylglycerol (TAG), chlorophyll, and protein content, and their cell sizes were recorded by coulter counter. We quantified heterogeneity of size and TAG content at single-cell level for a population of T. obliquus during a controlled standard batch cultivation. Unexpectedly, variability of TAG content per cell within the population increased throughout the batch run, up to 400 times in the final stage of the batch run, with values ranging from 0.25 to 99 pg · cell . Two subpopulations, classified as having low or high TAG content per cell, were identified. Cell size also increased during batch growth with average values from 36 to 70 μm · cell ; yet cell size variability increased only up to 16 times. Cell size and cellular TAG content were not correlated at the single-cell level. Our data show clearly that TAG production is affected by cell-to-cell variation, which suggests that its control and better understanding of the underlying processes may improve the productivity of T. obliquus for industrial processes such as biodiesel production.

The Community Structure of Picophytoplankton in Lake Fuxian, a Deep and Oligotrophic Mountain Lake

“…Consistent with our results, Eustigmatophyceae was reported to be a common member of the phytoplankton community in Lake Baikal and occurred throughout the year (Fietz et al, 2010). Chlorophyceae, including Volvox aureus and Tetradesmus obliquus , is widely distributed in the freshwater ecosystem, and the latter is considered a promising green microalgae for sustainable production of biofuels (Di et al, 2017).…”

The influence of phenols extracted from olive mill wastewater on the heterotrophic and mixotrophic growth of Scenedesmus sp.

“…Microalgae can grow under sunlight illumination achieving higher photosynthetic efficiency and productivity per hectare compared with superior plants . Microalgae belonging to the Scenedesmus genus are promising strains for industrial application because they can accumulate large amounts of industrially interesting compounds such as lipids (to up to 50%), starch (to up to 40%), proteins (to up to 60%), carotenoids (lutein, astaxanthin) and others . Moreover, this microalgae genus has proved to be cultivable on different wastewaters including, for example, olive mill wastewater (OMW), municipal wastewater and anaerobic digestion effluent .…”

Increasing Phosphorus Uptake Efficiency by Phosphorus-Starved Microalgae for Municipal Wastewater Post-Treatment

“…If high biomass productivity can be achieved, B. braunii is a suitable candidate for resource recovery from wastewater. Both A. falcatus and T. obliquus are often viewed as a potential species for high economic return due to their lipid productivity [ 33 , 34 ]. However, lower growth rate and productivity obtained in the present study deems them less appropriate for wastewater post-treatment with possible economical return.…”