Whole cell biocatalysts: essential workers from Nature to the industry

Abstract

SummaryMicroorganisms have been exposed to a myriad of substrates and environmental conditions throughout evolution resulting in countless metabolites and enzymatic activities. Although mankind have been using these properties for centuries, we have only recently learned to control their production, to develop new biocatalysts with high stability and productivity and to improve their yields under new operational conditions. However, microbial cells still provide the best known environment for enzymes, preventing conformational changes in the protein structure in non‐conventional medium and under harsh reaction conditions, while being able to efficiently regenerate necessary cofactors and to carry out cascades of reactions. Besides, a still unknown microbe is probably already producing a compound that will cure cancer, Alzeihmer's disease or kill the most resistant pathogen. In this review, the latest developments in screening desirable activities and improving production yields are discussed.

Biocatalytic conversion of cycloalkanes to lactones using an in‐vivo cascade in Pseudomonas taiwanensis VLB120

“…Although such in‐vitro cascade allows the highest flexibility to balance enzyme ratios for enhancing reaction performance (Muschiol et al, ), the necessity of several unit operations for the production of isolated enzymes and cofactors leads to high CapEx and OpEx costs. In this context, in‐vivo cascade offers economic perspectives by combining production and regeneration of enzymes and cofactors necessary to conduct cascade reactions in one single unit operation (Bayer, Milker, Wiesinger, Rudroff, & Mihovilovic, ; de Carvalho, ; Schrewe, Julsing, Bühler, & Schmid, ; Schrittwieser et al, ). However, for the efficient turnover of the in‐vivo cascade, the catalytic efficiency of the individual enzymes needs to be compatible to streamline substrate conversion toward the main product without accumulation of intermediate compounds.…”

Green synthesis of enantiopure quinoxaline alcohols using Daucus carota

“…11 Whole cell biocatalysts are advantageous over their isolated counterpart as whole cells accommodate the enzyme and cofactor within their microenvironment, whereas isolated enzymes require an external source of cofactor such as NADH/NADPH which becomes very expensive. 11 Whole cell biocatalysts are advantageous over their isolated counterpart as whole cells accommodate the enzyme and cofactor within their microenvironment, whereas isolated enzymes require an external source of cofactor such as NADH/NADPH which becomes very expensive.…”

Proteomic profiling of Sporotrichum thermophile under the effect of ionic liquids: manifestation of an oxidative stress response

“…In this context, the present approaches deal with the screening or engineering of enzymes which are stable in the presence of ILs so that the whole process can be carried out in a single pot (Xu et al 2016). Due to the high cost of enzymes, biocatalysis using microbial cells has recently gained momentum, since it is cost effective and maintains a native domain for functioning of enzymes (de Carvalho 2017). On similar lines, if the microbial cells are stable towards the ILs effect, the enzymes produced by them will also be active under such conditions thereby enabling the development of an in situ pre-treatment and saccharification approach.…”