Immobilized and Free Cells of Geotrichum candidum for Asymmetric Reduction of Ketones: Stability and Recyclability

Rapid Degradation of Hazardous Amides by Immobilized Engineered Pseudomonas putida KT2440 Based on a Novel Gene Expression Vector

The amides 4-trifluoromethylnicotinamide, acrylamide, and benzamide are widely used in agriculture and industry, posing hazards to the environment and animals. Immobilized bacteria are preferred in wastewater treatment, but degradation of these amides by immobilized engineered bacteria has not been explored. Here, engineered Pseudomonas putida KT2440 pLSJ15-amiA was constructed by introducing a new amidase gene expression vector into environmentally safe P. putida KT2440. P. putida KT2440 pLSJ15-amiA had high amidase activity, even at 80 °C. P. putida KT2440 pLSJ15-amiA immobilized with calcium alginate exhibited a greater environmental tolerance than free cells. The amides were rapidly degraded by the immobilized cells, but the activity was inhibited by high concentrations of substrates. The substrate inhibition model revealed that the optimum initial concentrations of 4-trifluoromethylnicotinamide, acrylamide, and benzamide for degradation by immobilized cells were 197.65, 350.76, and 249.40 μmol/L, respectively. This study develops a novel and excellent immobilized biocatalyst for remediation of wastewater containing hazardous amides.

Marine-derived fungi as biocatalysts

Marine microorganisms account for over 90% of ocean biomass and their diversity is believed to be the result of their ability to adapt to extreme conditions of the marine environment. Biotransformations are used to produce a wide range of high-added value materials, and marine-derived fungi have proven to be a source of new enzymes, even for activities not previously discovered. This review focuses on biotransformations by fungi from marine environments, including bioremediation, from the standpoint of the chemical structure of the substrate, and covers up to September 2022.

Enzymatic synthesis of enantiopure alcohols: current state and perspectives

Enantiomerically pure alcohols, as key intermediates, play an essential role in the pharmaceutical, agrochemical and chemical industries. Among the methods used for their production, biotechnological approaches are generally considered a green and effective alternative due to their mild reaction conditions and remarkable enantioselectivity. An increasing number of enzymatic strategies for the synthesis of these compounds has been developed over the years, among which seven primary methodologies can be distinguished as follows: (1) enantioselective water addition to alkenes, (2) enantioselective aldol addition, (3) enantioselective coupling of ketones with hydrogen cyanide, (4) asymmetric reduction of carbonyl compounds, (5) (dynamic) kinetic resolution of racemates, (6) enantioselective hydrolysis of epoxides, and (7) stereoselective hydroxylation of unactivated C-H bonds. Some recent reviews have examined these approaches separately; however, to date, no review has included all the above mentioned strategies. The aim of this mini-review is to provide an overview of all seven enzymatic strategies and draw conclusions on the effect of each approach.