Marine Bioprospecting, Biocatalysis and Process Development

Abstract

Oceans possess tremendous diversity in microbial life. The enzymatic machinery that marine bacteria present is the result of extensive evolution to assist cell survival under the harsh and continuously changing conditions found in the marine environment. Several bacterial cells and enzymes are already used at an industrial scale, but novel biocatalysts are still needed for sustainable industrial applications, with benefits for both public health and the environment. Metagenomic techniques have enabled the discovery of novel biocatalysts, biosynthetic pathways, and microbial identification without their cultivation. However, a key stage for application of novel biocatalysts is the need for rapid evaluation of the feasibility of the bioprocess. Cultivation of not-yet-cultured bacteria is challenging and requires new methodologies to enable growth of the bacteria present in collected environmental samples, but, once a bacterium is isolated, its enzyme activities are easily measured. High-throughput screening techniques have also been used successfully, and innovative in vitro screening platforms to rapidly identify relevant enzymatic activities continue to improve. Small-scale approaches and process integration could improve the study and development of new bioprocesses to produce commercially interesting products. In this work, the latest studies related to (i) the growth of marine bacteria under laboratorial conditions, (ii) screening techniques for bioprospecting, and (iii) bioprocess development using microreactors and miniaturized systems are reviewed and discussed.

Keywords: biocatalyst; bioprocess; cultivation; marine biotechnology; metagenomics.

Figure 1

New cultivation approaches for isolation of microbial species from marine environments.

Figure 2

Traditional and high-throughput approaches for screening and selection of biocatalysts from a library of isolates, and assessment of the best bioreaction conditions.

Figure 3

Conceptual visualization of the simultaneous number of biocatalysts to be tested during the different steps of the biocatalytic process development. At the early stages, a large number of putative candidates are tested, preferably by using high-throughput assays. After identification of the most active candidates, the effect of reaction conditions on kinetic data and biocatalyst stability are tested. The best candidate is then selected for the development of the production process, where biocatalyst formulation, reactor type and operation mode, and extraction and purification of product(s) are tested and defined.