(772f) Re-Use of Hydrothermal Liquefaction Bio-Char to Grow Galdieria Sulphuraria

Hydrothermal liquefaction is one of the promising methods to convert wet algal biomass into biofuels. Maximum biocrude oil was observed at 300⁰C when Galdieria Sulpuraria (GS) was liquefied using water as solvent. But a substantial amount of algal biomass was also converted into bio-char. The biochar produced at 300⁰C and 30 min of reaction time was analyzed for phosphorous content using inductively coupled plasma optical emission spectrometry (ICP-OES) and for nitrogen content using CHNOS elemental analyzer. It was observed that 1 gram of HTL biochar has 6.59mg of phosphorous and 6.36mg of nitrogen. The phosphorous and nitrogen present in this biochar can be used to cultivate microalgae. In this study, the macronutrients were leached using a 40 ml reactor at varying temperatures (23⁰C, 39⁰C and 55⁰C) and pH (2.5, 4.7 and 7.0) into cyanidium media without phosphates in it. This method was able to extract 54 mg/L of reactive phosphates and 16 mg/L of ammoniacal nitrogen at the optimum conditions. These leached phosphate and ammoniacal nitrogen were tested for the toxicity over 15 days and then used to grow GS in a Tissue Culture Roller drum apparatus with 16 mm borosilicate glass tube photo reactor and confirmed using a Microplate Assay at 40⁰C and 2-3 % COâ?? in an incubator. A better growth was observed when leached nutrients were used compared to that of regular nutrients in the growth media.