Sheldon Roger A
Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, P O Wits 2050, Johannesburg, South Africa Department of Biotechnology, Delft University of Technology, Julianalaan 136, Delft 2628BL, The Netherlands
J R Soc Interface. 2016 Mar;13(116). doi: 10.1098/rsif.2016.0087.
The grand challenge facing the chemical and allied industries in the twenty-first century is the transition to greener, more sustainable manufacturing processes that efficiently use raw materials, eliminate waste and avoid the use of toxic and hazardous materials. It requires a paradigm shift from traditional concepts of process efficiency, focusing on chemical yield, to one that assigns economic value to replacing fossil resources with renewable raw materials, eliminating waste and avoiding the use of toxic and/or hazardous substances. The need for a greening of chemicals manufacture is readily apparent from a consideration of the amounts of waste generated per kilogram of product (the E factors) in various segments of the chemical industry. A primary source of this waste is the use of antiquated 'stoichiometric' technologies and a major challenge is to develop green, catalytic alternatives. Another grand challenge for the twenty-first century, driven by the pressing need for climate change mitigation, is the transition from an unsustainable economy based on fossil resources--oil, coal and natural gas--to a sustainable one based on renewable biomass. In this context, the valorization of waste biomass, which is currently incinerated or goes to landfill, is particularly attractive. The bio-based economy involves cross-disciplinary research at the interface of biotechnology and chemical engineering, focusing on the development of green, chemo- and biocatalytic technologies for waste biomass conversion to biofuels, chemicals and bio-based materials. Biocatalysis has many benefits to offer in this respect. The catalyst is derived from renewable biomass and is biodegradable. Processes are performed under mild conditions and generally produce less waste and are more energy efficient than conventional ones. Thanks to modern advances in biotechnology 'tailor-made' enzymes can be economically produced on a large scale. However, for economic viability it is generally necessary to recover and re-use the enzyme and this can be achieved by immobilization, e.g. as solid cross-linked enzyme aggregates (CLEAs), enabling separation by filtration or centrifugation. A recent advance is the use of 'smart', magnetic CLEAs, which can be separated magnetically from reaction mixtures containing suspensions of solids; truly an example of cross-disciplinary research at the interface of physical and life sciences, which is particularly relevant to biomass conversion processes.
化学及相关行业在21世纪面临的重大挑战是向更绿色、更可持续的制造工艺转型，这种工艺要能高效利用原材料、消除废物并避免使用有毒有害物质。这需要从传统的工艺效率概念（侧重于化学产率）进行范式转变，转向一种将用可再生原材料替代化石资源、消除废物和避免使用有毒和/或有害物质赋予经济价值的理念。从化学工业各领域每千克产品产生的废物量（E因子）来考虑，化学品制造绿色化的需求显而易见。这种废物的一个主要来源是使用过时的“化学计量”技术，而一个重大挑战是开发绿色的催化替代技术。21世纪的另一项重大挑战是，由于迫切需要缓解气候变化，要从基于化石资源（石油、煤炭和天然气）的不可持续经济向基于可再生生物质的可持续经济转型。在这种背景下，目前被焚烧或填埋的废弃生物质的增值利用尤其具有吸引力。生物基经济涉及生物技术和化学工程交叉领域的跨学科研究，重点是开发用于将废弃生物质转化为生物燃料、化学品和生物基材料的绿色化学和生物催化技术。在这方面，生物催化有诸多优势。催化剂源自可再生生物质且可生物降解。反应过程在温和条件下进行，通常产生的废物较少，且比传统过程更节能。得益于生物技术的现代进展，“量身定制”的酶能够大规模经济地生产。然而，为了实现经济可行性，通常需要回收和再利用酶，这可以通过固定化来实现，例如制成固体交联酶聚集体（CLEAs），从而能够通过过滤或离心进行分离。最近的一项进展是使用“智能”磁性CLEAs，它可以从含有固体悬浮液的反应混合物中通过磁力分离；这确实是物理和生命科学交叉领域跨学科研究的一个例子，与生物质转化过程特别相关。
