Chemo-biocatalytic one-pot two-step conversion of cyclic amine to lactam using whole cell monoamine oxidase

BACKGROUND: Most biocatalysts currently involved in one‐pot chemoenzymatic cascades are pure enzymes, while whole cells and crude enzyme extracts remain unexplored. This work aims to develop a chemo‐biocatalytic one‐pot two‐step system involving whole cell monoamine oxidase (MAO, EC 1.4.3.4) coupled with a Cu‐based oxidative system (CuI/H2O2) for the transformation of 1,2,3,4‐tetrahydroisoquinoline (THIQ) to 3,4‐dihydroisoquinolin‐1(2H)‐one (DHIO). RESULTS: MAO‐N variants D9 and D11 were tested as whole cell and crude lysate biocatalysts for biological oxidation. Whole Escherichia coli OverExpress C43(DE3) cells expressing MAO‐N D9 showed the best performance (Vmax = 36.58 mmol L−1 h−1, KM = 8.124 mmol L−1, maximum specific productivity 89.3 μmol min−1 g−1DCW) and were employed in combination with CuI/H2O2 in a sequential one‐pot two‐step process. The biotransformation was scaled‐up to the initial volume of 25 mL and after triple THIQ feeding, 48.2 mmol L−1 of the intermediate 3,4‐dihydroisoquinoline (DHIQ) was obtained with a yield of 71.3%. Afterwards, chemical catalysts (1 mol% CuI and 10 eq. H2O2) were added to the biologically produced DHIQ, which was transformed to ∼30 mmol L−1 DHIO at 69.4% overall yield. CONCLUSION: As MAO‐N variants have wide substrate specificity, this work broadens the portfolio of one‐pot chemoenzymatic processes employing whole cell biocatalysts, representing an alternative to using pure enzymes

Biochar-mediated [C-14]atrazine mineralization in atrazine-adapted soils from Belgium and Brazil

Biochar addition to soil has been reported to reduce the microbial degradation of pesticides due to sorption of the active compound. This study investigated whether the addition of hardwood biochar alters the mineralization of C-14-labeled atrazine in two atrazine-adapted soils from Belgium and Brazil at different moisture regimens. Biochar addition resulted in an equally high or even in a significantly higher atrazine mineralization compared to the soils without biochar. Statistical analysis revealed that the extent of atrazine mineralization was more influenced by the specific soil than by the addition of biochar. It was concluded that biochar amendment up to 5% by weight does not negatively affect the mineralization of atrazine by an atrazine-adapted soil microflora