Application of environmental and economic metrics to guide the development of biocatalytic processes

Abstract

Abstract:The increasing industrial interest in biocatalytic processes is predominantly driven by the need for selective chemistry, with high reaction yield (Y reaction ) and few side reactions, as well as the need for optically pure chiral molecules (in particularly in the pharmaceutical industry). Interestingly, it is often argued that the mild conditions frequently used in biocatalytic reactions (ambient temperature and pressure, neutral pH and aqueous-based media) automatically lead to environmentally-friendly and cost-effective production processes. However, such a conclusion is not justified without the use of adequate tools to evaluate the performance of a process, in particular during process development. Nevertheless, at the early development stage, evaluation of biocatalytic processes is not a trivial task, not only due to the lack of data, but also because at this stage many of the biocatalytic processes are not yet fully optimized. Hence, in this paper we propose the use of a range of tools which can be used to guide process development, research tasks and support decision-making. Three sets of metrics are identified, each for use at different stages of process development (route selection, early development and late development), each with different objectives.

Scale‐up of industrial biodiesel production to 40 m3 using a liquid lipase formulation

“…The two reaction systems show similar biocatalyst yield. Of course operating at a higher biocatalyst loading will increase the reactor productivity (reducing the time that the reaction takes to reach completion) at the expense of increasing the biocatalyst cost contribution (Lima-Ramos et al, 2014). Hence there is a trade-off between the reactor productivity and the biocatalyst yield.…”

Green metrics analysis applied to the simultaneous liquid-phase etherification of isobutene and isoamylenes with ethanol over Amberlyst™ 35

“…AE measures how much of the starting material ends in the desired product, that is to say, how many atoms of the reactants are included in the structure of the final product. Hence, this parameter assesses the reaction stoichiometry as it does not consider either the reaction yields (ε), the side products produced, or other auxiliary materials used [13]. RME takes into account ε, the implicated masses of reactants and target product, and the actual molar quantities of reactants.…”

“…PMI is defined as the total mass of materials used to produce a specified mass of product and the C factor quantifies the amount of CO 2 produced per mass unit of product formed. Besides, there are other metrics such as the Energy Loss Index, that is an indicator to estimate the energy-related efforts associated with the process and the space time yield (STY) that assesses the speed at which reaction occurs [13].…”

“…Based on the definitions found in previous key publications [10,13,17,18,[20][21][22], the main parameters of the GMA (AE, ε, RME, SF, MRP, and VMR) were calculated as follow:…”

“…Many environmental and chemical factors must be considered simultaneously when selecting a synthetic route [10,11]. At the first step of development, the so-called "Green Chemistry Metrics" is a very useful tool to inform decisions making about the process design [12,13]. The metrics can be used during route (chemical pathway) selection, to compare between several options according to green principles, chemical and energetic efficiencies, since much deeper insights are gleaned about synthesis strategy if metrics are used.…”