Enhanced lipidic algae biomass production using gas transfer from a fermentative Rhodosporidium toruloides culture to an autotrophic Chlorella protothecoides culture

Abstract

In order to produce single-cell oil for biodiesel, a yeast and a microalga were, for the first time, grown in two separate reactors connected by their gas-phases, taking advantage of their complementary nutritional metabolisms, i.e., respiration and photosynthesis. The yeast Rhodosporidium toruloides was used for lipid production, originating a carbon dioxide-enriched outlet gas stream which in turn was used to stimulate the autotrophic growth of Chlorella protothecoides in a vertical-alveolar-panel (VAP) photobioreactor. The microalgal biomass productivity was 0.015 gL(-1)h(-1), and its lipid productivity attained 2.2 mgL(-1)h(-1) when aerated with the outlet gas stream from the yeast fermenter. These values represent an increase of 94% and 87%, respectively, as compared to a control culture aerated with air. The CO2 bio-fixed by the microalgal biomass reached an estimated value of 29 mgL(-1)h(-1) in the VAP receiving the gas stream from the fermenter, a value 1.9 times higher than that measured in the control VAP.

Production of carotenoids and lipids by Dunaliella tertiolecta using CO2 from beer fermentation

“…The pH of the microalgae cultures was measured coinciding with the highest peaks of CO 2 production in the yeast cultivations. The variation of pH in microalgae cultures is the result of bicarbonate-carbonate equilibrium, which depends on the balance between CO 2 supplied in the inlet gas stream and the CO 2 uptake rate of the microalgae [18]. The pH of CO 2 -enriched cultures oscillated between 7.0 and 9.0.…”

“…Integrated systems using the CO 2 -enriched gas exit of aerobic cultures to aerate autotrophic microalgae cultures were successfully tested recently [16][17][18], and CO 2 from bioethanol produced from sugarcane fermentation was used for the continuous cultivation of Arthrospira platensis [19][20][21].…”

Co-culture for lipid production: Advances and challenges

“…In the case of heterotrophic and photoautotrophic microorganisms in a separate photobioreactor, respective cultures produced gases while growing. Autotrophically grown C. protothecoides improved biomass productivity (15 g m À3 h À1 ) and lipid productivity (2.2 g m À3 h À1 ) when aerated with the off-gas from Rhodosporidium toruloides, in comparison with the same culture aerated entirely with air and without exchanging gases [69]. The improvement of lipid productivity of C. protothecoides grown autotrophically and aerated with the CO 2 -enriched air from its heterotrophic culture was above 55% for biomass and lipid yield when compared with the bioreactor aerated only with air [70].…”

“…Symbiosis of yeast and algae was well studied by many authors [21,69,70] and reviews elucidated the benefits of microbial association of two species to improve the growth rate and biomass concentration [18,19]. Successful combination between microalgae and yeasts are given in Table 2.…”

Estudio de las características morfológicas y fisiológicas de Chlorella protothecoides orientado hacia la producción de lípidos para biocombustible

“…Los principales estímulos que afectan el crecimiento de estos microorganismos son la temperatura, la intensidad luminosa, la deficiencia de nutrientes (nitrógeno, fósforo, azufre y silicio), la salinidad, la concentración de CO 2 y el pH del medio de cultivo, de estos la deficiencia de nitrógeno es el principal factor que incide en el metabolismo de los lípidos (Loera-Quezada & Olguín, 2010). Santos et al (2013) comprobaron que un aumento en la concentración de CO 2 en la entrada de aire de un cultivo autotrófico de Chlorella protothecoides incrementó la productividad de biomasa y lípidos en 94% y 87% respectivamente, en comparación con el control.…”