Enhancement of Chlorella vulgaris Biomass Cultivated in POME Medium as Biofuel Feedstock under Mixotrophic Conditions

Abstract

Microalgae cultivated in mixotrophic conditions have received significant attention as a suitable source of biofuel feedstock, based on their high biomass and lipid productivity. POME is one of the wastewaters generated from palm oil mills, containing important nutrients that could be suitable for mixotrophic microalgae growth. The aim of this research was to identify the growth of Chlorella vulgaris cultured in POME medium under mixotrophic conditions in relation to a variety of organic carbon sources added to the POME mixture. The research was conducted with 3 different carbon sources (D-glucose, crude glycerol and NaHCO 3) in 40% POME, monitored over 6 days, under an illumination of 3000 lux, and with pH = 7. The biomass was harvested using an autoflocculation method and dry biomass was extracted using an ultrasound method in order to obtain the lipid content. The results show that C. vulgaris using D-glucose as carbon source gained a lipid productivity of 195 mg/l/d.

Opportunities and Challenges of Microalgal Cultivation on Wastewater, with Special Focus on Palm Oil Mill Effluent and the Production of High Value Compounds

“…Several studies reported the cultivation of microalgae on photo-heterotrophic conditions during which microalgae utilize light and organic carbon as the source of energy. Also, Nur and Hadiyanto [104] reported that C. vulgaris biomass was enhanced during photo-heterotrophic cultivation by adding D-glucose to POME medium as a co-organic substrate that was mixed with air, containing CO 2 . Sukumaran et al [144] reported that the addition of 4% raw POME to the medium of Spirulina platensis changed the condition into heterotrophic growth due to the dark color that inhibited irradiance exposure.…”

Ozone Application for Tofu Waste Water Treatment and Its Utilisation for Growth Medium of Microalgae Spirulina sp

“…For direct method, the oxidation is carried out by ozone itself that dissolved in water. While indirect method, the oxidation occurs by producing OH radicals that would oxidize other compounds [6]. The longer the ozonation time, the more ozone will be formed that will oxidize the compound, resulting in lower COD values due to the simpler compounds.…”

“…The efficiency of ozone higly depends on pH as an indication of hydrogen ion activity. A high pH will facilitate the formation of OH radicals because the presence of OH ions can initiate ozone decomposition as a first step in the production of OH radicals [6], whereas at low pH the ozone molecule remains as its initial oxidant.…”

Potency of Botryococcus braunii cultivated on palm oil mill effluent wastewater as a source of biofuel

“…This is due to the effect of POME that acts as auto-inhibition substrate. In addition, the higher POME concentration generates cultivation mode from mixotrophic to slightly heterotrophic condition [11]. When the light was not provided in media, microalgae start consuming organic carbon as the source of energy in the heterotrophic condition.…”

“…Several researchers reported the potential of POME as promoting media for microalgae growth [8,9]. Moreover, the wastewater can provide the mixotrophic mode for microalgae medium due to the content of organic carbon [11].…”