Enhancement of C-phycocyanin productivity by Arthrospira platensis when growing on palm oil mill effluent in a two-stage semi-continuous cultivation mode

Abstract

Palm oil mill effluent (POME) is well known as agricultural wastewater that has a high potential as a medium for microalgal growth due to its high macro-and micronutrient content. The cyanobacterium Arthrospira platensis is considered as a species with a high C-phycocyanin (C-PC) content which is important for fine chemical and pharmaceutical applications. However, cultivation of A. platensis on POME to produce economically feasible amounts of C-PC has not been well explored. For this, environmental, nutritional, and cultivation modes (batch, semi-continuous) were varied to optimize C-PC productivity when cultivated at various POME concentrations. Arthrospira platensis was found to grow well on POME. Highest biomass and C-PC concentrations were found on 30-100% POME. Central composite rotatable design (CCRD) response surface methodology demonstrated that C-PC productivity was influenced by urea addition at the optimum salinity. The highest C-PC productivity was found on 100% POME during semi-continuous cultivation, while the addition of phosphorus and urea did not significantly improve C-PC productivity. By applying semi-continuous cultivation with 50% POME at the first stage and 100% POME at the second stage, a similarly high C-PC productivity (4.08 ± 1.3 mg L −1 day −1) was achieved as compared with (artificial) Zarrouk medium during batch cultivation. We conclude that, when using a two-stage semi-continuous cultivation process, A. platensis can produce economically feasible amounts of C-PC when cultivated on 100% POME.

Utilization of anaerobically digested dairy manure wastewater for Spirulina maxima cultivation

“…The productivity of phycocyanin from S. maxima in various dilutions of ADDMW ranged from 1.04 to 1.39 mg L -1 day -1 . The result from this study is still in the range of Nur et al [21] reported data. The purity of phycocyanin was shown in the purity index, a ratio between the absorbance of phycocyanin at the maximum wavelength (620 nm) and the absorbance of phycocyanin at 280 nm (protein) [22].…”

Influence of photodegradation on the removal of color and phenolic compounds from palm oil mill effluent by Arthrospira platensis

“…The initial pH was adjusted to 9.0 ± 0.2 by using 2 N HCl or 2 N NaOH. Salinity was adjusted to 20 PSU as optimum level by using NaCl based on previous results (Nur et al 2019a). External urea (800 mg L −1 ) was added to the medium to avoid nitrogen limitation based on previous experiments (Nur et al 2019a).…”

“…Salinity was adjusted to 20 PSU as optimum level by using NaCl based on previous results (Nur et al 2019a). External urea (800 mg L −1 ) was added to the medium to avoid nitrogen limitation based on previous experiments (Nur et al 2019a). Every day, the optical density of the culture was measured at 750 nm to determine the growth rate.…”

“…Dry biomass was measured indirectly based on optical density as described previously (Nur et al 2019a). Since POME may strongly interfere with the A. platensis absorption measurements, samples (3 mL) were taken and centrifuged at 10,000 rpm for 15 min to separate the algal biomass from the POME medium.…”

“…Furthermore, information on the ability of A. platensis to degrade phenolic compounds is lacking. At the same time, this species synthesizes high value-added compounds such as phycocyanin (Sukumaran et al 2018;Nur et al 2019a). The aim of this research was therefore to explore and optimize the utilization of A. platensis to remove color and phenolic compounds from POME by varying nutritional and environmental conditions.…”