First Sentence

"Over the last 20 years, many reservations with respect to biocatalysis have been voiced, contending that: (i) enzymes only feature limited substrate specificity; (ii) there is only limited availability of enzymes; (iii) only a limited number of enzymes exist; (iv) protein catalyst stability is limited; (v) enzymes reactions are saddled with limited space-time yield; and (vi) enzymes require complicated co-substrates such as cofactors."