ABSTRACT
Biocatalysis (enzymatic and whole cell catalysis) has been extensively applied in white biotechnology for the production of fuels and ne chemicals in recent years.1 Furthermore, biocatalysis is currently on the policy agendas because it is considered one of the most promising routes for a bio-based economy. Biocatalysis plays a key role in the development of biorenery for conversion of biomass into a wide array of fuels, chemicals, and materials.2-4 Expanding from traditional applications, biocatalysis is nowadays providing the initial steps toward the production of chemicals commodities5,6 for sustainable energy supply and environment of long-term care throughout the world. Consequently, the importance of biocatalysis as a biotechnological tool on biomass transformation is increasingly every day as well.7,8
Chemical production from biomass can be followed on two different directions, which are the biomass biodegradation and further the biotransformation of the biomass derivatives to nal value-added products (Scheme 7.1). The rst refers to the
7.1 Introduction .................................................................................................. 163 7.2 Immobilized Enzymes as Biocatalysts ......................................................... 164 7.3 Nanosupports for Heterogeneous Biocatalysts ............................................. 165 7.4 Immobilization Approach ............................................................................. 167 7.5 Biofuels Derived from the Biocatalytic Conversion of Biomass Using
Nanoheterogeneous Designed Biocatalysts .................................................. 171 7.5.1 Biodiesel ........................................................................................... 171 7.5.2 Bioethanol ......................................................................................... 172
7.6 Biomass Derivatives as Added-Value Products as a Result of Using Nanoheterogeneous Designed Biocatalysts (Glycerol Conversion to Value-Added Products) ................................................................................. 173
7.7 Conclusions ................................................................................................... 174 References .............................................................................................................. 174
enzymatic treatments of cellulose, starch, lignin, chitin, protein, and oils, directly components of the biological sources, whereas the second category includes the biocatalytic conversion of simple molecules derived from biomass components, e.g., free sugars, organic acids, and alcohols.6 For both directions, biocatalysis provides substantial advantages compared with chemical catalysis, such as high efciency, high degree of selectivity (e.g., regio-, chemo-, and enantio-), “green” reaction conditions (i.e., mild reaction conditions) and thus low energy consumption. Besides less waste amounts and production of toxic wastes, biocatalytic processes led to high atom economy reactions. Nowadays, these are the main characteristic for the biotransformations.9 Moreover, the heterogeneous design of the biocatalyst (e.g., immobilized enzyme) avoids the product contamination and provides the possibility to recover the biocatalyst and its reuse in successive reaction cycles, with often improving the operational stability and shelf-life.10 Consequently, under these conditions, a low amount of biomaterial (enzyme or whole cell) is requested for the biocatalyst preparation, thus leading to a low cost of the technology.
