Two-Stage Cultivation of Dunaliella tertiolecta with Glycerol and Triethylamine for Lipid Accumulation: a Viable Way To Alleviate the Inhibitory Effect of Triethylamine on Biomass

Abstract

Microalgae are promising alternatives for sustainable biodiesel production. Previously, it was found that 100 ppm triethylamine greatly enhanced lipid production and lipid content per cell of Dunaliella tertiolecta by 20% and 80%, respectively. However, triethylamine notably reduced biomass production and pigment contents. In this study, a two-stage cultivation with glycerol and triethylamine was attempted to improve cell biomass and lipid accumulation. At the first stage with 1.0 g/liter glycerol addition, D. tertiolecta cells reached the late log phase in a shorter time due to rapid cell growth, leading to the highest cell biomass (1.296 g/liter) for 16 days. However, the increased glycerol concentrations with glycerol addition decreased the lipid content. At the second-stage cultivation with 100 ppm triethylamine, the highest lipid concentration and lipid weight content were 383.60 mg/liter and 37.7% of dry cell weight (DCW), respectively, in the presence of 1.0 g/liter glycerol, which were 27.36% and 72.51% higher than those of the control group, respectively. Besides, the addition of glycerol alleviated the inhibitory effect of triethylamine on cell morphology, algal growth, and pigment accumulation in D. tertiolecta. The results indicated that two-stage cultivation is a viable way to improve lipid yield in microalgae. IMPORTANCE Microalgae are promising alternatives for sustainable biodiesel production. Two-stage cultivation with glycerol and triethylamine enhanced the lipid productivity of Dunaliella tertiolecta, indicating that two-stage cultivation is an efficient strategy for biodiesel production from microalgae. It was found that glycerol significantly enhanced cell biomass of D. tertiolecta, and the presence of glycerol alleviated the inhibitory effect of triethylamine on algal growth. Glycerol, the major byproduct from biodiesel production, was used for the biomass accumulation of D. tertiolecta at the first stage of cultivation. Triethylamine, as a lipid inducer, was used for lipid accumulation at the second stage of cultivation. Two-stage cultivation with glycerol and triethylamine enhanced lipid productivity and alleviated the inhibitory effect of triethylamine on the algal growth of D. tertiolecta, which is an efficient strategy for lipid production from D. tertiolecta.

Functional Identification of Two Types of Carotene Hydroxylases from the Green Alga Dunaliella bardawil Rich in Lutein

“…Dunaliella cells were grown in a defined medium containing 1.5 M NaCl (as normal condition) at 26 °C and 8000 lx provided by cool-white fluorescent lamps under a 14/ 10 h light/dark cycle for about 2 weeks. 5,35 The optical density (OD) of algal sample was determined by using a spectrophotometer (Agilent, USA) at 630 nm (OD 630 ).…”

“…The salt-tolerant green alga Dunaliella bardawil strain FACHB-847 was purchased from Freshwater Algae Culture Collection at the Institute of Hydrobiology (FACHB), Chinese Academy of Sciences. Dunaliella cells were grown in a defined medium containing 1.5 M NaCl (as normal condition) at 26 °C and 8000 lx provided by cool-white fluorescent lamps under a 14/10 h light/dark cycle for about 2 weeks. , The optical density (OD) of algal sample was determined by using a spectrophotometer (Agilent, USA) at 630 nm (OD 630 ).…”

Antioxidant Production in Dunaliella

“…Low growth rate and productivity of Dunaliella strain [4,28,174] relative to other sources (such as fungus, yeast) [178][179][180][181] and selection of a suitable strain; ii. Transferring lab-scale optimised abiotic stress strategies to a commercial scale;…”

“…Commercially, Dunaliella is cultivated in several countries, such as Australia, China, Israel, and India, with pilot-scale projects in Chile, Spain, Iran and Portugal [24][25][26] and considered one of the best sources of β carotene. Dunaliella has also been suggested as a sustainable source for industrial bioprocessing for the production of protein [27], biodiesel [4,28,29], colouring agent [30], and antioxidants [31].…”

Visual Detection of Triethylamine and a Dual Input/Output Logic Gate Based on a Eu3+-Complex

“…In suitable cases, by regulating the energy of the ligand and the outer stimulations, the energy transfer between the ligands and the Ln-metal centers can be controlled, leading the emission to be “Off-On”, or leading to a change in color and intensity [ 20 ], which leads to the emission becoming a favorable and promising candidate for visual detection [ 21 , 22 ]. Furthermore, the detection of toxic triethylamine (TEA) [ 23 ] possesses a direct relevance to the quality of the environment and our lives and is highly demanding [ 24 ]. However, the development of stimuli-responsive systems that show a wide range of luminescent color changes for sensitive and eye-catching observations upon TEA stimulations are still worth studying [ 17 , 25 , 26 ].…”