in addition to the above, if transesterified correctly and the fatty acid content is significantly saturated, than keep it luke warm or add proper additive

Dear Ajit kaur

Heterogeneous catalyst, enzymatic catalyst and SCFs are not bother about FFA level of oils. But if you use homogeneous base catalysts for high FFA oils, Two-stage processes(acid and alkali transesterification) are to be considered.

Hello madam. Did you perform two-step transesterification? If it happens after a two-step transesterification, you need to check the conversion percentage of that biodiesel. I think the conversion is not complete. Every oil has its specific properties and it varies from sample to sample. So, there is also a possibility of saponification reaction in your experiment. Please feel free to contact me if you need to do any more discussion. You can also get some ideas from my paper attached herewith.

Article Production of biodiesel from unused algal biomass in Punjab, India

Rachan

Trans-esterification of triglycerides (TAG) from vegetables oil or fats to fatty acid methyl ester (FAME) is done with the addition of alcohol i.e. methanol. Triacylglycerols are primary ingredients of niger oil and they are chemically esters of fatty acids with glycerol

6g of  Sodium Hydroxide (NaOH) pellets are to be added to 300ml methyl alcohol to form a solution having the base catalyst which is a methoxide mixture.1litre of niger oil(madhuca oil) at 600 C is to be added to methoxide and filtered from glycerin layer. This is acid washed with 5ml of concentrated sulphuric acid. This leads to neutralization reaction leaving salt and water. Now the salt has to be separated and biodiesel is washed with warm water at 400 C. Then it is heated up to 1100 C to remove water by evaporation to obtain biodiesel.