Sulfated exopolysaccharide production and nutrient removal by the marine diatom Phaeodactylum tricornutum growing on palm oil mill effluent

Abstract

Palm oil mill effluent (POME) is the major source of environmental hazard in palm oil industry. Yet, due to its high nutrient content, POME may offer opportunities for the growth of algae as a source of value-added compounds such as sulfated extracellular polysaccharide (sEPS) while simultaneously removing valuable nutrients such as phosphate. The aim of this paper was to evaluate growth, total sEPS production, and nutrient removal by the diatom Phaeodactylum tricornutum grown on POME under a range of experimental conditions (temperature, salinity, supplementation of extra nutrients). Phaeodactylum tricornutum was found to grow well on a range of POME concentrations, with 30% POME as optimum concentration. Nitrate and urea addition enhanced both growth rate and final biomass, whereas phosphate significantly stimulated growth only at low temperature. Box-Behnken response surface methodology revealed that interactions between temperature and salinity, and between temperature and urea influenced sEPS production. The highest total sEPS (140 mg L −1) concentration was recorded at 25°C, 2.6% salinity, and 100 mg L −1 urea addition. Our study shows that POME wastewater, supplemented with urea at relatively high temperatures, can be considered as a potential medium for P. tricornutum to replace commercial nutrients while producing high amounts of sEPS and removing almost 90% of phosphorous from the wastewater.

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

“…In support of this, Carvalho et al (2004) reported that A. platensis can tolerate an ammonia concentration of 6.4 mM (109 mg L −1 ) whereas growth was totally inhibited at 26 mM. In contrast, previous research had shown that the growth of other algal species was inhibited when using more than 30 and 50% v/v of digested POME (Cheirsilp et al 2017;Cheah et al 2018;Nur et al 2019b). This underlines the tolerance of Arthrospira to the high ammonia levels or other potentially toxic substances (e.g., phenolic compounds) present in POME.…”

“…Prior to experimental use, POME was thawed and filtered (GF/C glass fiber filter, Whatman) for removal of suspended solids and autoclaved at 121°C for 15 mins. The wastewater contained 1245 mg L −1 COD, 72.4 mg L −1 total N, and 7.93 mg L −1 PO 4 3-P, as estimated previously using appropriate assay kits LCK349 and LCK138 (Hach Lange) (Nur et al 2019b).…”

Low-cost production of cell-bound lipases by pure and co-culture of yeast and bacteria in palm oil mill effluent and the applications in bioremediation and biodiesel synthesis

“…Whereas COD level is usually at the range of 40,000-50,000 mg/L, where in this research, the COD concentration was higher at 67,145 mg/L than other COD measured in other researches such as 37,000-48,000 g/L [9] and 55,230 mg/L [44]. In addition, many studies have tried to utilize POME as a nutrient for culture fermentation media such as Bacillus cereus MF661883 to produce lipid [51], Phaeodactylum tricornutum (microalgae) to produce sulfated extracellular polysaccharide (eSPS) [70], and Aspergillus oryzae whole cells expressing Candida antartica lipase B (r-CALB) to produce immobilized wholecell biocatalysts [53] (Table 1). POME contains many organic materials, such as O&G, carbohydrates, free fatty acids (FFAs), highly concentrated nitrogenous compounds, and minerals (e.g., K, N, Mg, Ca, P, Fe, B, Zn, Mn, and Cu) that can support the growth of heterotrophic microorganisms, a potential substrate for microbial biomass, and could be beneficial for the cultivation of various types of microorganisms according to several studies [40,44,51,71].…”

Valorization of Wastewater Resources Into Biofuel and Value-Added Products Using Microalgal System

“…In a study on microalgae Botryococcus braunii strain CCALA 220 (race A), a yield of 2 mg L −1 was obtained at optimum conditions of 950 µmol m −2 s −1 of light intensity and 6 mM of nitrate (Cepák and Přibyl, 2018). Another study gives a yield of 140 mg L −1 of EPS with Phaeodactylum tricornutum grown in palm oil mill effluent (Nur et al, 2019).…”

“…gives a maximum yield of 650 mg L −1 from MMT effluent wastewater source (biofertilizer) whereas Phaeodactylum sp. when grown in palm oil mills (wastewater source) yields 140 mg L −1 of exopolysaccharides (Das et al, 2019;Nur et al, 2019). The biofuel produced from municipal wastewater effluent by C. reinhardtii (bio-oil) produces 505 mg L −1 under the optimum conditions (Kong et al, 2010).…”