Improved Biocatalytic Activity of the Debaryomyces Species in Seawater

Abstract

Biocatalysis is an environmentally friendly strategy widely used in the chemical and pharmaceutical industries. One of its approaches consists in utilizing whole cells, which usually involves the consumption of large quantities of water. Oceans cover a large part of the Earth's surface, and constitute an important reservoir that can be used as an alternative to freshwater in chemical reactors. This work analyzed the behavior of several yeast halotolerant species belonging to genera Debaryomyces and Schwanniomyces in both freshwater and seawater. It concluded that these microorganisms were more resistant to organic solvents/compounds in the second medium. Their metabolic activity was also greater, which made the reduction reaction of several prochiral ketones more effective. Besides, yeasts cells displayed better performance in subsequent recycling steps, which could help reduce the costs of the process.

Whole‐Cell Biocatalysis in Seawater: New Halotolerant Yeast Strains for the Regio‐ and Stereoselectivity Reduction of 1‐Phenylpropane‐1,2‐Dione in Saline‐Rich Media

“…A broader analysis was carried out using all these biocatalysts at different temperatures in freshwater and seawater (Table and Figures 2S–3S). Our previous study found that halotolerant species Debaryomyces and Schwanniomyces showed better thermotolerance in the second medium . This study confirms a similar behavior for all the strains considered when reactions were performed at 45 °C.…”

“…Encouraged by our previous results by using seawater as a solvent in reactions catalyzed by Debaryomyces and Schwanniomyces species, we checked the ability of six yeast strains ( Saccharomyces cerevisiae FY86, Pichia fermentans , Pichia glucozyma , Kluyveromyces marxianus , Meyerozyma guilliermondii , and Torulaspora delbrueckii ) to grow in the presence of NaCl, the main component of seawater. Plates with the rich medium usually employed for yeast growth (YPD, see the Experimental section), which contained salt concentrations between 0 and 7.5 % ( w / v ) were used for this purpose.…”

“…The four found halotolerant strains were used to catalyze the reduction of 1‐phenylpropane‐1,2‐dione ( 1 ) at 30 °C and for 2 h using seawater and freshwater as reaction media in the presence of glucose (2 %, w / v ). The Debaryomyces ( D. fabryi and D. hansenii ) and Schwanniomyces ( S. etchellsii and S. polymorphus ) species used by our group in previous studies done in seawater were also employed under these standard conditions. The results shown in Figure indicate that all the strains were capable of catalyzing the reaction in both media and of showing some regioselectivity.…”

“…These microorganisms were also more resistant to organic solvents/reagents in seawater than in freshwater, and their metabolic activity was also greater in the first medium. These facts indicate the possibility of using such strains as biocatalysts in seawater where, in addition, yeast cells displayed better performance to be efficiently recycled …”

“…Oceans constitute the most important reservoir of biodiversity in nature, with microorganisms adapted to high salinity that can be used in biotechnological applications to perform bioprocesses under salinity conditions . Recently, the ability of whole cells of marine and other halotolerant yeasts to perform biocatalytic processes in seawater has been described by us and other authors . In our previous works, we used several Debaryomyces and Schwanniomyces halotolerant yeast strains for some biocatalytic processes using seawater as a solvent.…”