Sorry if I have caused some concern, I have a little food additive book and it states that Disodium Ribonucleotide may be animal derived.
Check this link for more info
http://www.foodfigures.com/food_additive/E635_Disodium-5_ribonucleotide_262.htm
however I'd do your own research prior, personally anything that contains anything chemical sounding has me concerned.
Perhaps Sanitarium would like to clarify.