Characterization of a Recombinant Trehalose Synthase from Arthrobacter chlorophenolicus and its Unique Kinetics Indicating a Substrate Cooperativity

Characterization of cold-active trehalose synthase from Pseudarthrobacter sp. for trehalose bioproduction

Trehalose is a functional sugar that has numerous applications in food, cosmetic, and pharmaceutical products. Production of trehalose from maltose via a single-step enzymatic catalysis using trehalose synthase (TreS) is a promising method compared with the conventional two-step process due to its simplicity with lower formation of byproducts. In this study, a cold-active trehalose synthase (PaTreS) from Pseudarthrobacter sp. TBRC 2005 was heterologously expressed and characterized. PaTreS showed the maximum activity at 20 °C and maintained 87% and 59% of its activity at 10 °C and 4 °C, respectively. The enzyme had remarkable stability over a board pH range of 7.0-9.0 with the highest activity at pH 7.0. The activity was enhanced by divalent metal ions (Mg2+, Mn2+ and Ca2+). Conversion of high-concentration maltose syrup (100-300 g/L) using PaTreS yielded 71.7-225.5 g/L trehalose, with 4.5-16.4 g/L glucose as a byproduct within 16 h. The work demonstrated the potential of PaTreS as a promising biocatalyst for the development of low-temperature trehalose production, with the advantages of reduced risk of microbial contamination with low generation of byproduct.

Production of Trehalose from Maltose by Whole Cells of Permeabilized Recombinant Corynebacterium glutamicum

Trehalose (α-D-glucopyranosyl-1,1-α-D-glucopyranoside) is a stable and nonreducing disaccharide; can be used as sweetener, stabilizer, and humectant; and has many applications in the food, pharmaceutical, and cosmetic industries. Trehalose production from maltose catalyzed by trehalose synthase (TreS) is simple and economically feasible for industrial-scale application. Reducing the cost and enhancing the efficiency of TreS synthesis and the conversion of maltose to trehalose is critical for trehalose production. In this study, the homologous TreS was constitutively overexpressed in Corynebacterium glutamicum ATCC13032 by removing the repressor gene lacIq fragment in the plasmid, and TreS expression could be exempt from the inducer addition and induction process. For cell permeabilization, Triton X-100 was used as a permeabilization agent, and the treatment time was 3 h. In the conversion system, the permeabilized cells of recombinant C. glutamicum were used as biocatalysts, 300 g/L maltose was used as a substrate, and 173.7 g/L trehalose was produced within 12 h under 30 °C and pH 7.0 conditions. In addition, the whole-cell biocatalysts showed promising reusability. This study provides a safe, convenient, practical, and low-cost pathway for the production of trehalose.

Programming an Orthogonal Self-Assembling Protein Cascade Based on Reactive Peptide-Protein Pairs for In Vitro Enzymatic Trehalose Production

Trehalose is an important rare sugar that protects biomolecules against environmental stress. We herein introduce a dual enzyme cascade strategy that regulates the proportion of cargos and scaffolds, to maximize the benefits of enzyme immobilization. Based upon the self-assembling properties of the shell protein (EutM) from the ethanolamine utilization (Eut) bacterial microcompartment, we implemented the catalytic synthesis of trehalose from soluble starch with the coimmobilization of α-amylase and trehalose synthase. This strategy improved enzymatic cascade activity and operational stability. The cascade system enabled the efficient production of trehalose with a yield of ∼3.44 g/(L U), 1.5 times that of the free system. Moreover, its activity was maintained over 12 h, while the free system was almost completely inactivated after 4 h, demonstrating significantly enhanced thermostability. In conclusion, an attractive self-assembly coimmobilization platform was developed, which provides an effective biological process for the enzymatic synthesis of trehalose in vitro.

Screening, Cloning, Expression and Characterization of New Alkaline Trehalose Synthase from Pseudomonas monteilii and Its Application for Trehalose Production

Trehalose is a non-reducing disaccharide in increasing demand for applications in food, nutraceutical, and pharmaceutical industries. Single-step trehalose production by trehalose synthase (TreS) using maltose as a starting material is a promising alternative process for industrial application due to its simplicity and cost advantage. Pseudomonas monteilii TBRC 1196 was identified using the developed screening method as a potent strain for TreS production. The TreS gene from P. monteilii TBRC 1196 was first cloned and expressed in Escherichia coli. Purified recombinant trehalose synthase (PmTreS) had a molecular weight of 76 kDa and showed optimal pH and temperature at 9.0 and 40°C, respectively. The enzyme exhibited >90% residual activity under mesophilic condition under a broad pH range of 7-10 for 6 h. Maximum trehalose yield by PmTreS was 68.1% with low yield of glucose (4%) as a byproduct under optimal conditions, equivalent to productivity of 4.5 g/l/h using enzyme loading of 2 mg/g substrate and high concentration maltose solution (100 g/l) in a lab-scale bioreactor. The enzyme represents a potent biocatalyst for energy-saving trehalose production with potential for inhibiting microbial contamination by alkaline condition.

Molecular cloning and biochemical characterization of a trehalose synthase from Myxococcus sp. strain V11

The tresI gene of Myxococcus sp. strain V11 was cloned, and found to encode a trehalose synthase comprising 551 amino acids. The deduced molecular weight of the encoded TreS I protein 64.7 kDa and the isoelectric point (pI) was predicted to be 5.6. The catalytic cleft consists of the Asp202-Glu244-Asp310 catalytic triad and additional conserved residues. The recombinant (His)₆-tag enzyme was expressed in Escherichia coli BL21(DE3) and purified by Ni²⁺-affinity chromatography, resulting in a specific activity of up to 172.7 U/mg. TLC and HPLC results confirmed that rTreS I can convert maltose into trehalose, with a yield of 61%. The K_M and V_max values of recombinant TreS I for maltose were 0.62 mM and 25.5 mM min^-1 mg^-1 protein, respectively. TreS I was optimally active at 35° and stable at temperatures of <25 °C. TreS I was stable within a narrow range of pH values, from 6.0 to 7.0. The enzymatic activity was slightly stimulated by Mg²⁺ and strongly inhibited by Fe³⁺, Co²⁺ and Cu²⁺. TreS I was also strongly inhibited by SDS and weakly by EDTA and TritonX-100.