Process for improved seaweed biomass conversion for fuel intermediates, agricultural nutrients and fresh water

An integrated process for the production of fuel intermediates, agri-nutrients and potable water from the fresh biomass of Kappaphycus alvarezii seaweed comprising the steps of:

• i. expelling of the seaweed juice from the fresh biomass by the known method of mechanically shearing of the seaweed and filtering the resultant slurry to obtain residual biomass and sea weed juice;
• ii. extracting pristine κ-carrageenan from residual biomass as obtained in step (i) using seawater under autoclaved condition at temperature range of 105° C.-120° C. at pressure in the range of 25 to 35 kPa for period in the range of 50 to 70 minute followed by precipitating with Isopropyl alcohol (IPA) to obtain pristine κ-carrageenan;
• iii. treating 5-10% (w/v) pristine κ-carrageenan as obtained in step (ii) with aqueous acid catalyst under autoclave condition at temperature in the range of 100-110° C. for period in the range of 1-3 hour to obtain 5-hydroxymethyl furfural (HMF), galactose and additional amount of bisulphate as potassium bisulphate generated from the substrate itself;
• iv. extracting the HMF as obtained in step (iii) in pure form with organic solvent and thereafter neutralizing the generated bisulphate in aqueous phase with magnesium hydroxide;
• v. charging fresh lot of κ-carrageenan into the aqueous phase and repeating the process of step (iii) and continuing in this manner over several cycles using the same organic layer or fresh solvent for HMF extraction;
• vi. neutralizing the aqueous layer to neutral pH with magnesium hydroxide;
• vii. adding seaweed juice to shift the equilibrium of the composition of the aqueous phase from schoenite to potassium sulphate and carrying out thermal distillation to recover potassium sulphate in pure form;
• viii. recovering galactose in pure form by known method of concentration and crystallisation or converting it into ethanol by known methods or treating the aqueous phase with acid catalyst under autoclave condition to convert galactose into levulinic acid and formic acid;
• ix. neutralizing the spent aqueous layer, recovering magnesium hydroxide and thereafter fortifying the surplus juice with the nutrient rich aqueous stream.