Permeabilized whole cells containing co-expressed cyclomaltodextrinase and maltooligosyltrehalose synthase facilitate the synthesis of nonreducing maltoheptaose (N-G7) from ß-cyclodextrin.
J Sci Food Agric
; 103(14): 7061-7069, 2023 Nov.
Article
em En
| MEDLINE
| ID: mdl-37337412
ABSTRACT
BACKGROUND:
Maltodextrin is an important bulk ingredient in food and other industries; however, drawbacks such as uneven polymerization and high reducibility limit its utilization. Nonreducing maltoheptaose (N-G7) is a good substitute for maltodextrin owing to its single degree of polymerization and its nonreducing properties. In this study, in vitro cell factory biotransformation of ß-cyclodextrin (ß-CD) to N-G7 is demonstrated using coexpressed cyclomaltodextrinase (CDase, EC 3.2.1.54) and maltooligosyltrehalose synthase (MTSase, EC 5.4.99.15). However, the cell membrane prevents ß-CD from entering the cell owing to its large diameter.RESULTS:
The amylase-deficient permeabilized host ΔycjM-ΔmalS-ΔlpxM is utilized for the coexpression of recombinant CDase and MTSase. Deletion of lpxM effectively allows the entry of ß-cyclodextrin into the cell, despite its large diameter, without requiring any relevant cell membrane permeability-promoting reagent. This results in a 28.44% increase in the efficiency of ß-CD entry into the cell, thus enabling intracellular N-G7 synthesis without the extracellular secretion of recombinant CDase and MTSase. After reacting for 5.5 h, the highest purity of N-G7 (65.50%) is obtained. However, hydrolysis decreases the purity of N-G7 to 49.30%, thus resulting in a conversion rate of 40.16% for N-G7 when the reaction lasts 6 h. Precise control of reaction time is crucial for obtaining high-purity N-G7.CONCLUSION:
Whole-cell catalysis avoids cell fragmentation and facilitates the creation of an eco-friendly, energy-efficient biotransformation system; thus, it is a promising approach for N-G7 synthesis. © 2023 Society of Chemical Industry.Palavras-chave
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Glucanos
/
Glicosídeo Hidrolases
Idioma:
En
Ano de publicação:
2023
Tipo de documento:
Article