Techno-Economic Evaluation of the PHB Production from Milk Whey and Glycerol As feedstocks

One of the most important applications of oil are as petrochemically-derived polymers, which due to their non-biodegradability cause a major environmental problem. Hence, natural polymers or those originated from microorganisms, such as polyhydroxyalkanoates have increased its industrial value. One of the main problems associated to the industrial production of biopolymers like Poly-hydroxybutyrate (PHB), is the high cost of raw materials and the energy consumed in its production. One alternative to solve these problems is the use of different agroindustrial wastes as substrate, such as glycerol from the biodiesel production and whey from the cheese processing. To test the feasibility of PHB production and thereby raise the techno-economic analyses, Bacillus megaterium growth curves were carried out using 20% glycerol and a PHB accumulation of 3.24 g/L, was observed after 42 h. When whey was used as substrate, a PHB accumulation of 1.5 g/L was observed after 26h. The techno-ecomomic evaluation was performed for the production and purification of PHB and demonstrated that the production costs are between 1.9 and 4.0 U.S./kg, depending on the raw material used, being higher for whey due to the need of pre-treatment processes to reduce the amount of nitrogen.