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Biocatalytic conversion of cycloalkanes to lactones using an in‐vivo cascade in Pseudomonas taiwanensis VLB120
Author(s) -
Karande Rohan,
Salamanca Diego,
Schmid Andreas,
Buehler Katja
Publication year - 2018
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.26469
Subject(s) - chemistry , cyclohexanone , cyclohexanol , cyclooctane , biocatalysis , monooxygenase , cascade reaction , organic chemistry , stereochemistry , cyclohexane , catalysis , enzyme , cytochrome p450 , reaction mechanism
Chemical synthesis of lactones from cycloalkanes is a multi‐step process challenged by limitations in reaction efficiency (conversion and yield), atom economy (by‐products) and environmental performance. A heterologous pathway comprising novel enzymes with compatible kinetics was designed in Pseudomonas taiwanensis VLB120 enabling in‐vivo cascade for synthesizing lactones from cycloalkanes. The respective pathway included cytochrome P450 monooxygenase (CHX), cyclohexanol dehydrogenase (CDH), and cyclohexanone monooxygenase (CHXON) from Acidovorax sp. CHX100. Resting (non‐growing) cells of the recombinant host P. taiwanensis VLB120 converted cyclohexane, cyclohexanol, and cyclohexanone to ϵ‐caprolactone at 22, 80–100, and 170 U g CDW −1 , respectively. Cyclohexane (5 mM) was completely converted with a selectivity of 65% for ϵ‐caprolactone formation in 2 hr without accumulation of intermediate products. Promiscuity of the whole‐cell biocatalyst gave access to analogous lactones from cyclooctane and cyclodecane. A total product concentration of 2.3 g L −1 and a total turnover number of 36,720 was achieved over 5 hr with a biocatalyst concentration of 6.8 g CDW L −1 .