Development and economic evaluation of an eco-friendly biocatalytic synthesis of emollient esters.

During the past decades the understanding and prospects of enzyme-catalysed reactions have been massively widened and there are a number of implemented large-scale enzymatic processes mainly based in the use of commercial biocatalysts. As it might happen that the same process can be successfully carried out by different commercial lipases, the election of the biocatalyst must rely on productivity and economic considerations. This work presents productiveness and direct operation cost evaluation as a key tool for the selection between two commercial lipase catalysts, the versatile but expensive Novozym ^®  435 and a much more economical option, Lipozyme ^®  TL IM, in the synthesis of spermaceti, a mixture of emollient esters with cosmetic applications. Proving that Novozym ^®  435 leads to minimum savings of 10% with respect to the cheapest immobilized derivative, biocatalyst cost does not appear to be the major contribution to the economics of the processes under study, due to their great capacity to be recovered and reused. At laboratory scale, the biggest economic investment is caused by substrates, which can be massively reduced at industrial scale by using bulk reagents. In such case, energy cost may be the major contribution to the process economy. This work proposes an optimized process ready to be scaled-up in order to accurately determine the energetic requirements of the possible industrial enzymatic synthesis.