NOVELTY - Forming fuel intermediate, agri-nutrient and potable water involves: i) expelling fresh biomass of Kappaphycus alvarezii seaweed juice from fresh biomass to obtain residue; ii) extracting pristine kappa-carrageenan from residue; iii) treating it with aqueous acid catalyst to give 5-hydroxymethyl furfural (HMF)/galactose/bisulphate; iv) extracting HMF in pure form with solvent; v) charging fresh lot of kappa-carrageenan into aqueous phase; vi) neutralizing; vii) adding seaweed juice; viii) recovering galactose, and converting into levulinic acid/formic acid; and ix) neutralizing.    USE - For production of 5-hydroxymethyl furfural (HMF), potassium sulfate (K2SO4), levulinic acid and formic acid as fuel intermediates, agri-nutrients and potable water from the fresh biomass of Kappaphycus alvarezii seaweed (claimed).    ADVANTAGE - In the process, levulinic acid and formic acid are co-produced in 80-85% yield with respect to galactose present; and carbon utilization efficiency is 80-85% for 5-hydroxymethyl furfural (HMF), levulinic acid and formic acid taken together, whereas the carbon utilization is 60-62% for levulinic acid and formic acid production directly from kappa-carrageenan. Distillation of organic solvents used in the process may be undertaken using solar thermal energy also. The thermal energy requirement is met through combustion of additional supplies of granular biomass. Electrical energy requirement for bipolar electro-dialysis (ED) and other purposes is also obtainable through gasification of the granular biomass. Combustion or gasification of granule gives additionally sulfuric acid (H2SO4) and ash rich in glasserite fertilizer. The by-product aqueous stream after conducting all operations is blended with surplus juice leading to zero effluent discharge and simultaneous fortification of the juice for foliar spray application.    DETAILED DESCRIPTION - An integrated process for production of fuel intermediates, agri-nutrients and potable water from the fresh biomass of Kappaphycus alvarezii seaweed involves: i) expelling 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 Kappa-carrageenan from residual biomass as obtained in step (i) using seawater under autoclaved condition at 105-120 degrees C and at a pressure of 25-35 kPa for 50-70 minutes followed by precipitating with isopropyl alcohol (IPA) to obtain pristine kappa-carrageenan; iii) treating 5-10 wt./wt.% pristine kappa-carrageenan as obtained in step (ii) with aqueous acid catalyst under autoclave condition at 100-110 degrees C for 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 then neutralizing the generated bisulphate in aqueous phase with magnesium hydroxide; v) charging fresh lot of kappa-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 sulfate and carrying out thermal distillation to recover potassium sulfate in pure form; viii) recovering galactose in pure form by known method of concentration and crystallization or converting it into ethanol by known methods or treating aqueous phase with acid catalyst under autoclave condition to convert galactose into levulinic acid and formic acid; and ix) neutralizing the spent aqueous layer, recovering magnesium hydroxide and then fortifying the surplus juice with the nutrient rich aqueous stream.