compositions of bio - lubricating fluids for machining operations , free of oils and emulsifiers , that have a high refrigeration and lubricating property with synergetic association of water , biopolymers and proper additives , endowing the product with biodegradability wherein said composition comprises between 0 . 01 and 5 . 0 % w / w of a biopolymer , between 0 . 5 and 25 . 0 % w / w of an anticorrosive additive , and additives that depend on the application of the bio - lubricating fluid , which may be anticorrosive , biocidal , antifoaming , extreme pressure , ph controlling , complexing , and other additives , and water qsp .