Heterotrophic production of Chlorella sp. TISTR 8990—biomass growth and composition under various production conditions

Abstract

The green microalga Chlorella sp. TISTR 8990 was grown heterotrophically in the dark using various concentrations of a basal glucose medium with a carbon-to-nitrogen mass ratio of 29:1. The final biomass concentration and the rate of growth were highest in the fivefold concentrated basal glucose medium (25 g L glucose, 2.5 g L KNO ) in batch operations. Improving oxygen transfer in the culture by increasing the agitation rate and decreasing the culture volume in 500-mL shake flasks improved growth and glucose utilization. A maximum biomass concentration of nearly 12 g L was obtained within 4 days at 300 rpm, 30°C, with a glucose utilization of nearly 76% in batch culture. The total fatty acid (TFA) content of the biomass and the TFA productivity were 102 mg g and 305 mg L day , respectively. A repeated fed-batch culture with four cycles of feeding with the fivefold concentrated medium in a 3-L bioreactor was evaluated for biomass production. The total culture period was 11 days. A maximum biomass concentration of nearly 26 g L was obtained with a TFA productivity of 223 mg L day . The final biomass contained (w/w) 13.5% lipids, 20.8% protein and 17.2% starch. Of the fatty acids produced, 52% (w/w) were saturated, 41% were monounsaturated and 7% were polyunsaturated (PUFA). A low content of PUFA in TFA feedstock is required for producing high quality biodiesel. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1589-1600, 2017.

Dynamic flux balance analysis of biomass and lipid production by Antarctic thraustochytrid Oblongichytrium sp. RT2316‐13

“…The maximum lipid productivity of RT2316-13 did not (Table 1). This was comparable to photoautotrophically grown microalgae for which lipid productivity ranged from 11.4 to 82.0 mg•L −1 •day −1 (Govindan et al, 2020), although microalgae do display much higher productivities when grown heterotrophically (Bouyam, Choorit, Sirisansaneeyakul, & Chisti, 2017).…”

Production of Renewable Lipids by the Diatom Amphora copulata

“…The specific growth rate (µ) was calculated as the slope of a plot of ln C b versus time, during exponential growth [54].…”

“…The lipids were extracted from biomass samples that had been washed and freezedried. The Bligh and Dyer [55] method as previously used for lipid recovery from numerous microalgae [4,52,54,56,57], was used. Briefly, 0.2 g of freeze-dried biomass was suspended in a solvent mixture (chloroform 1 mL, methanol 2 mL, deionized water 0.8 mL), vortex mixed for 2 min and allowed to rest for 4 h at room temperature.…”

“…The triglycerides in the freeze-dried (Section 2.5) biomass were converted in situ to fatty acid methyl esters (FAME) and extracted [54]. Thus, 50 mg dry biomass was mixed with 5 mL of toluene/acidified methanol (1:2 v/v; methanol was acidified by mixing 1.8 mL concentrated sulfuric acid with 100 mL methanol) and kept at 50 • C overnight [54]. This slurry was extracted three times with 3 mL of hexane each time.…”

“…[4]. In contrast, most of the other microalgae in Table 3 (i.e., A. coffeaeformis, A. subtropica, C. vulgaris, C. minor, C. fusiformis, N. gaditana, N. oculata, N. salina, Neochloris sp., P. tricornutum, and P. simplex) were grown purely photoautotrophically, and their oil productivity would likely increase greatly in heterotrophic or mixotrophic growth as has been demonstrated for some of them [14,54,[100][101][102]. Pseudococcomyxa simplex 5 127.0 22.9…”