Optimization of Total Carotenoid Production by Halorubrum Sp. TBZ126 Using Response Surface Methodology

Abstract

Carotenoids are one of the most diverse and broadly distributed classes of pigments in nature with a high number of biotechnological applications. Carotenoids have a broad range of functions, especially in relation to human health and their role as biological antioxidants. The increasing demand for consumption of natural carotenoids has raised interest in their bio-production. The objective of the present study was the analysis of environmental factors (temperature, pH and salinity) through response surface methodology (RSM) on the total carotenoid production of Halorubrum sp. TBZ126. In addition the effect of light was evaluated. Five levels of temperature, pH, and salinity were selected based on central composite design (CCD) and RSM to reach the optimum values for the cell growth and carotenoid production. Bio-production was carried out in an orbital shaker using a 10% (v/v) inoculum, and agitation at 120 rpm for 9 days in a non-illuminated environment. Dry cell weight was determined and total carotenoid was estimated by spectrophotometer. The production of biomass ranged from 0.04 to 0.84 g/l and the total carotenoid from 0.15 to 10.78 mg/l. The optimum conditions for cell growth and total carotenoid production in Halorubrum sp. TBZ126 cultures, were temperature 31ºC and 32ºC, pH 7.51 and 7.94 and NaCl (w/v) 18.33% and 20.55%, respectively. In conclusion, employing RSM design and under the light exposure as an inducing factor, carotenoid production by Halorubrum sp. TBZ126 was elevated by 45%. Additionally, TBZ126 could produce carotenoids at lower concentrations of NaCl (as low as 2.5%), in the absence of sodium acetate without elevating magnesium sulfate concentration.

Characterization of a bacterioruberin‐producing Haloarchaea isolated from the marshlands of the Odiel river in the southwest of Spain

“…Similar results have been observed for Haloferax alexandrinus which exhibited high growth and carotenoid production under shaking conditions, reaching 2.06 mg total carotenoids g −1 DW . Halorubrum sp TBZ126 also showed higher concentrations of carotenoids upon optimized growth conditions, reaching 11.71 mg L −1 of total carotenoids …”

“…Others strains of Halorubrum showed a similar range of growth temperature, for example Halorubrum alkaliphilum grows at an optimal temperature of 38°C but is able to grow between 20 and 44°C, Halorubrum luteum is able to grow between 33 and 37°C, Halorubrum sfaxense growth at optimal temperature of 37°C but is able to grow at 20–55°C and Halorubrum sp. TBZ126 is able to grow at 31–32°C . As shown in Figures g,h, light intensity has no significant effect on growth, but it influences on the total carotenoid content, which is about 25% higher in cells illuminated with light intensities of 200 µE m −2 s −1 than in cells grown in the dark, increasing from 20 to 25 mg L −1 .…”

In vitro dual (anticancer and antiviral) activity of the carotenoids produced by haloalkaliphilic archaeon Natrialba sp. M6

“…Sikkander et al used a Box-Behnken design to determine the optimum factors affecting carotenoid production by Halorubrum sp. TBZ126, and the estimated coefficients and the corresponding p-values indicated that X1 (temperature), X2 (pH) and X3 (salinity) were significant factors for both cell growth and carotenoid production by this strain 15 . After extraction, the orange pigment in this study was characterized using FTIR, Raman spectroscopy, GC-MS, LC-MS and NMR methods.…”

Marine Bacteria versus Microalgae: Who Is the Best for Biotechnological Production of Bioactive Compounds with Antioxidant Properties and Other Biological Applications?

“…Halophilic Archaea, from the families Halobacteriaceae and Haloferacaceae, have a red color that is mostly results from a special carotenoid they contain named "bacterioruberin". As recent investigations regarding the production of bacterioruberin show, the production of this rare carotenoid might be simply improved by enforcing modifications on light frequency, oxygen availability, pH, salinity, or temperature [41,223]. Furthermore, Haloarchaea are also organisms that produce several rare carotenoids such as salinixanthin [37,38].…”