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Amylosucrase fromThe online version contains supplementary material available at 10.1007/s10068-022-01113-z.

Luteolin is the most abundant phytochemical phenolic compound contained within peanut hulls and has broad pharmacological characteristics and high bioavailability. In this study, the extraction conditions for luteolin from peanut hulls were optimized. The effects of methanol concentration and reaction temperature on luteolin solubility were determined using the central composite design (CCD) under response surface methodology. Luteolin content within in the extracts increased with increasing temperature and organic solvent-to-water ratios. The optimal conditions for luteolin extraction were 81°C and 87.5% methanol for a predicted extraction value of 174.51 mg/100 g, which was within 1.25% of the experimental value of 172.35 mg/100 g, confirming the predicted model. Additionally, compared to conventional stirring, the luteolin content of reflux-extracted peanut hull had a higher extraction efficiency by 42.50%. The antioxidant compound contents and antioxidant capacity of the extracts were also determined, with the effects of temperature and solvent concentration increasing along with the extracted luteolin. In this study, CCD optimized the conditions for obtaining luteolin from peanut hulls, suggesting that the improved extraction efficiency of the bioactive compound can expand the use of peanut shells in the nutraceutical and food industries.

The transglycosylation activity of Deinococcus geothermalis amylosucrase (DgAS) expressed in Corynebacterium glutamicum (cDgAS) was optimized for luteolin glycoside synthesis using purified enzymes (PEs), whole cells (WCs) suspended in buffer (WCB) and WCs in ethanol (WCE). Unlike PE, both WCB and WCE had high transglycosylation yields exceeding 95% over a wide temperature range, with cells in ethanol exhibiting the greatest enzymatic activity for up to 48 h due to membrane degradation and the slow release of cDgAS, which led to lysis and death. Meanwhile, in buffer, protection of the cytoplasmic membrane and ideal pH conditions maintained activity for over 200 h. To improve their performance, WCs were immobilized on agarose and the resulting immobilized cells (ICs) had high stability in organic solvents, although WCB possessed greater thermal stability at 50 °C. The reaction parameters for PE, WCE, WCB, and IC transglycosylation were optimized using response surface methodology, and ICs required lower concentrations of substrates while synthesizing higher concentrations of reaction products in addition to producing the novel compound luteolin maltotrioside after several cycles of reuse. This study expanded on the range of possibilities for the industrial application of C. glutamicum in increasing the production and bioavailability of novel and improved products.

Amylosucrase (ASase, E.C. 2.4.1.4) is a powerful transglycosylation enzyme that can transfer glucose from sucrose to the hydroxyl (-OH) group of various compounds. In this study, recombinant ASases from Deinococcus geothermalis (DgAS) and Bifidobacterium thermophilum (BtAS) were used to synthesize biosurfactants based on the computational analysis of predicted docking simulations. Successful predictions of the binding affinities, conformations, and three-dimensional structures of three surfactants were computed from receptor-ligand binding modes. DgAS and BtAS were effective in the synthesis of biosurfactants from glyceryl caprylate, glyceryl caprate, and polyglyceryl-2 caprate. The results of the transglycosylation reaction were consistent for both ASases, with glyceryl caprylate acceptor showing the highest concentration, as confirmed by thin layer chromatography. Furthermore, the transglycosylation reactions of DgAS were more effective than those of BtAS. Among the three substrates, glyceryl caprylate glycoside and glyceryl caprate glycoside were successfully purified by liquid chromatography–mass spectrometry (LC–MS) with the corresponding molecular weights.

Carotenoids, which have biologically beneficial effects and occur naturally in microorganisms and plants, are pigments widely applied in the food, cosmetics and pharmaceutical industries. The compound 4,4′-diaponeurosporene is a C30 carotenoid produced by some Lactobacillus species, and Lactobacillus plantarum is the main species producing it. In this study, the antioxidant activity of 4,4′-diaponeurosporene extracted from L. plantarum subsp. plantarum KCCP11226 was examined. Maximum carotenoid content (0.74 ± 0.2 at A470) was obtained at a relatively low temperature (20°C). The DPPH radical scavenging ability of 4,4′-diaponeurosporene (1 mM) was approximately 1.7-fold higher than that of butylated hydroxytoluene (BHT), a well-known antioxidant food additive. In addition, the ABTS radical scavenging ability was shown to be 2.3- to 7.5-fold higher than that of BHT at the range of concentration from 0.25 mM to 1 mM. The FRAP analysis confirmed that 4,4′-diaponeurosporene (0.25 mM) was able to reduce Fe3+ by 8.0-fold higher than that of BHT. Meanwhile, 4,4′-diaponeurosporene has been confirmed to be highly resistant to various external stresses (acid/bile, high temperature, and lysozyme conditions). In conclusion, L. plantarum subsp. plantarum KCCP11226, which produces 4,4′-diaponeurosporene as a functional antioxidant, may be a potentially useful strain for the development of functional probiotic industries.

1-Deoxynojirumycin (1-DNJ) is a representative iminosugar with α-glucosidase inhibition (AGI) activity. In this study, the full genome sequencing of 1-DNJ-producing Bacillus velezensis K26 was performed. The genome consists of a circular chromosome (4,047,350 bps) with two types of putative virulence factors, five antibiotic resistance genes, and seven secondary metabolite biosynthetic gene clusters. Genomic analysis of a wide range of Bacillus species revealed that a 1-DNJ biosynthetic gene cluster was commonly present in four Bacillus species (B. velezensis, B. pseudomycoides, B. amyloliquefaciens, and B. atrophaeus). In vitro experiments revealed that the increased mRNA expression levels of the three 1-DNJ biosynthetic genes were closely related to increased AGI activity. Genomic comparison and alignment of multiple gene sequences indicated the conservation of the 1-DNJ biosynthetic gene cluster in each Bacillus species. This genomic analysis of Bacillus species having a 1-DNJ biosynthetic gene cluster could provide a basis for further research on 1-DNJ-producing bacteria.

Resistant starch (RS) is a complex prebiotic carbohydrate beneficial to the human gut. In the present study, four genes encoding for putative amylolytic enzymes, likely to be responsible for RS-degradation, were identified in the genome of Bifidobacterium adolescentis P2P3 by comparative genomic analysis. Our results showed that only three enzymes (RSD1, RSD2, and RSD3) exhibited non-gelatinized high amylose corn starch (HACS)-degrading activity in addition to typical α-amylase activity. These three RS-degrading enzymes (RSD) were composed of multiple domains, including signal peptide, catalytic domain, carbohydrate binding domains, and putative cell wall-anchoring domains. Typical catalytic domains were conserved by exhibiting seven typical conserved regions (I-VII) found mostly in α-amylases. Analysis of enzymatic activity revealed that RSD2 displayed stronger activity toward HACS-granules than RSD1 and RSD3. Comparative genomics in combination with enzymatic experiments confirmed that RSDs might be the key enzymes used by RS-degrading bifidobacteria to degrade RS in a particular ecological niche, such as the human gut.

Amylosucrase (ASase, E.C. 2.4.1.4) is capable of efficient glucose transfer from sucrose, acting as the sole donor molecule, to various functional acceptor compounds, such as polyphenols and flavonoids. An ASase variant from Deinococcus geothermalis, in which the 226th alanine is replaced with asparagine (DgAS-A226N), shows increased polymerization activity due to changes in the flexibility of the loop near the active site. In this study, we further investigated how the mutation modulates the enzymatic activity of DgAS using molecular dynamics and docking simulations to evaluate interactions between the enzyme and phenolic compounds. The computational analysis revealed that the A226N mutation could induce and stabilize structural changes near the substratebinding site to increase glucose transfer efficiency to phenolic compounds. Kinetic parameters of DgAS-A226N and WT DgAS were determined with sucrose and 4-methylumbelliferone (MU) as donor and acceptor molecules, respectively. The kcat/Km value of DgAS-A226N with MU (6.352 mM-1min-1) was significantly higher than that of DgAS (5.296 mM-1min-1). The enzymatic activity was tested with a small phenolic compound, hydroquinone, and there was a 1.4-fold increase in α-arbutin production. From the results of the study, it was concluded that DgAS-A226N has improved acceptor specificity toward small phenolic compounds by way of stabilizing the active conformation of these compounds.

Enzymatic hydrolysis and self-assembly are considered promising methods for preparation of starch nanoparticles (SNPs) because they are environmentally friendly, and time- and cost-effective. These methods are based on the self-assembly of short-chain glucans released from the α-1,6 bonds in amylopectin. Since their discovery, many studies have described the structural and physicochemical properties of self-assembled SNPs. Self-assembled SNPs can be prepared by two methods: using only the soluble portion containing the short-chain glucans, or using the whole hydrolyzate including both insoluble and soluble fractions. Although the structural and physical properties of self-assembled SNPs can be attributed to the composition of the hydrolyzates that participate in self-assembly, this aspect has not yet been discussed. This review focuses on SNPs self-assembled with only soluble short-chain glucans and addresses their characteristics, including formation mechanisms as well as structural and physicochemical properties, compared with SNPs prepared with total hydrolyzates.

Amylosucrase (AS) catalyzes the transfer of a glucosyl unit from sucrose onto α-1,4-linked glucan polymers in starch. In this study, AS from Deinococcus geothermalis (DgAS) was applied to produce modified rice starches with slowly digestible properties. DgAS-treated waxy and normal rice starches showed significantly (p

A total of 262 bacterial strains were isolated from clay minerals, bentonite and zeolite, in Gyeongsangbukdo, Republic of Korea, and their hydrolytic enzyme activities were analyzed. Most of the isolated strains belonged to Micrococcales and Bacillales order. Of strains, 96 strains produced α-amylase activity, 42 strains showed cellulase activity, 111 strains had pectinase activity, and 70 strains showed protease activity. Among them, 177 isolates exhibited one or more of the hydrolytic enzyme activities and in particular Bacillus cereus MBLB1321, B. albus MBLB1326 and KIGAM017, B. mobilis MBLB1328, MBLB1329 and MBLB1330 showed all of the enzyme activities. These results demonstrate the diversity of functional Bacillus species in clay minerals as vital sources for the discovery of industrially valuable hydrolytic enzymes, which have a great commercial prospect in various bio-industrial applications.

Modification of chestnut starch with amylosucrase from Deinococcus geothermalis (DGAS) increases the proportion of resistant starch. DGAS-modified chestnut starch (DMCS) attenuates obesity in diet-induced obese mice via a receptor of short chain fatty acids (SCFAs), G-protein-coupled receptor 43. SCFAs are gut microbial metabolites produced by fermenting resistant starch and have key roles in the obesity-ameliorating effects of DMCS. Here, we evaluated the mechanical links among DMCS-induced changes in the gut microbiota, consequent production of microbial metabolites, and host genetic responses. Supplementation with DMCS altered the proportions of cecal microbiota, such as Ruminococcaceae and Bacteroides; microbial metabolites, such as acetic acid; and some carbohydrate metabolites. DMCS also induced changes in the expression of some genes in cecal epithelial cells, including genes involved in energy production, the cell cycle, and cellular junctions. Changes in the gut microbiota, microbial metabolites, and host gene expression were found to be significantly correlated. Our findings demonstrated the integrated and incorporated association among the gut microbiota, their beneficial metabolites, and the host transcriptome, which contributed to clarifying the anti-obesity effects of DMCS as a prebiotic. Therefore, fortifying resistant starch by modification of chestnut starch using DGAS may be a good strategy in the functional food industry.

Amylosucrase (AS; EC 2.4.1.4) is an enzyme that has great potential in the biotechnology and food industries, due to its multifunctional enzyme activities. It can synthesize α-1,4-glucans, like amylose, from sucrose as a sole substrate, but importantly, it can also utilize various other molecules as acceptors. In addition, AS produces sucrose isomers such as turanose and trehalulose. It also efficiently synthesizes modified starch with increased ratios of slow digestive starch and resistant starch, and glucosylated functional compounds with increased water solubility and stability. Furthermore, AS produces turnaose more efficiently than other carbohydrate-active enzymes. Amylose synthesized by AS forms microparticles and these can be utilized as biocompatible materials with various bio-applications, including drug delivery, chromatography, and bioanalytical sciences. This review not only compares the gene and enzyme characteristics of microbial AS, studied to date, but also focuses on the applications of AS in the biotechnology and food industries.

Resistant starch (RS) in the diet reaches the large intestine and is fermented by the gut microbiota, providing beneficial effects on human health. The human gut bacterium FMB-CY1 was isolated and identified as a new species closest to Ruminococcus bromii. Ruminococcus sp. FMB-CY1 completely degraded RS including commercial RS types 2, 3, and 4, and generated glucose and maltose; however, it did not assimilate glucose. Genome analysis revealed 15 amylolytic enzymes (Amy) present in FMB-CY1. The evolutionary trees revealed that the Amys were well divided each other. All Amys (4, 9, 10, 12, and 16) containing cohesin and/or dockerin and scaffolding proteins known to be involved in constituting the amylosome, were identified. A new species of Ruminococcus, strain FMB-CY1, was considered to have the ability to form amylosomes for the degradation of RS. This new RS-degrading Ruminococcus species provides insights into the mechanism(s) underlying RS degradation in the human gut. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10068-021-01027-2.

A putative type II pullulanase gene, pulP, was identified in Bifidobacterium adolescentis P2P3. PulP possesses an α-amylase domain at the N-terminus and a pullulanase type I domain at the C-terminus, as well as three carbohydrate-binding modules (one CBM25 and two CBM41s) between them. The native PulP and four truncated mutant recombinant proteins (PulPΔCΔP, PulPΔP, PulPΔAΔC, and PulPΔA), in which each of the two catalytic domains and/or the CBMs were deleted, were produced in Escherichia coli and their specific properties were characterized. The removal of either catalytic domain abolished the corresponding catalytic activity of the wild-type enzyme. Deletion of the C-terminal domain resulted in a drastic decrease in the optimal temperature and thermostability, indicating that the pullulanase domain might be related to the temperature dependency of the enzyme. In addition, the elimination of the CBMs in the mutant proteins led to a loss of binding affinity toward raw substrates as well as the loss of their hydrolysis activities compared to the wild-type enzyme. HPAEC and TLC analyses proved that PulP and its mutants could hydrolyze α-glucans into maltotriose as their main product. These results suggest that PulP may play an important role in α-glucan metabolism in B. adolescentis P2P3.

Resistant starch (RS) is metabolized by gut microbiota and involved in the production of short-chain fatty acids, which are related to a variety of physiological and health effects. Therefore, the availability of RS as a prebiotic is a topic of interest, and research on gut bacteria that can decompose RS is also important. The objectives in this study were 1) to isolate a human gut bacterium having strong degradation activity on non-gelatinized RS, 2) to characterize its RS-degrading characteristics, and 3) to investigate its probiotic effects, including a growth stimulation effect on other gut bacteria and an immunomodulatory effect. Bifidobacterium adolescentis P2P3 showing very strong RS granule utilization activity was isolated. It can attach to RS granules and form them into clusters. It also utilizes high-amylose corn starch granules up to 63.3%, and efficiently decomposes other various types of commercial RS without gelatinization. In a coculture experiment, Bacteroides thetaiotaomicron ATCC 29148, isolated from human feces, was able to grow using carbon sources generated from RS granules by B. adolescentis P2P3. In addition, B. adolescentis P2P3 demonstrated the ability to stimulate secretion of Th1 type cytokines from mouse macrophages in vitro that was not shown in other B. adolescentis. These results suggested that B. adolescentis P2P3 is a useful probiotic candidate, having immunomodulatory activity as well as the ability to feed other gut bacteria using RS as a prebiotic.

Carotenoids are organic pigments with antioxidant properties and are widespread in nature. Here, we isolated five microbes, each forming yellow-colored colonies and harboring C30 carotenoid biosynthetic genes (crtM and crtN). Thereafter, Lactobacillus plantarum subsp. plantarum KCCP11226, which showed the highest carotenoid production, was finally selected and the produced pigment was identified as C30 carotenoid 4,4'-diaponeurosporene. This strain exhibited the highest survival rate under oxidative stress and its carotenoid production was also enhanced after exposure to 7 mM H2O2. Moreover, it showed the highest ability to scavenge DPPH free radical. Our results suggested that L. plantarum subsp. plantarum KCCP11226, which produces 4,4'-diaponeurosporene as a natural antioxidant, may be a functional probiotic.

In this study, we improved the polymerization activity of Deinococcus geothermalis amylosucrase (DGAS) via semi-rational design to support increased potential industrial applications. Structural analysis selected three amino acid residues (Pro219, Phe225, and Ala226) in loop 3 of the B domain that were considered to be related to polymerization activity. Various DGAS variants were constructed through site-saturated mutagenesis, from which two mutants (DGAS-P219Y and DGAS-A226N) with increased polymerization activity were selected by fluorescence screening. DGAS-A226N synthesized longer amylose-like polymers from sucrose than those from wild-type (WT) DGAS. A kinetic study of sucrose as a substrate showed that the ratio of polymerization to hydrolysis activity of DGAS-A226N was significantly higher than that of WT DGAS. DGAS-A226N exhibited its highest enzymatic activity at 50 °C; its half-life was 6.8 min at 60 °C, and its melting temperature was 61.16 ± 0.09 °C. Computational simulation analysis of DGAS-A226N indicated that its conformation was more compact than that of WT DGAS, possibly owing to decreased flexibility of loops 2, 3, 4, 7, and 8. Thus, conformational changes in DGAS-A226N allowed the production of longer oligosaccharides, which may support a broader range of industrial application by affording novel or improved product characteristics.

Ruminococcus is one of the keystone bacteria of the human colonic microbiota and is highly specific for utilization of resistant starch via formation of amylosomes. Here, we present the characteristics of an extracellular amylase, Rbamy5, in Ruminococcus bromii. In an in silico study, it showed low homology with any other known amylases, but it was evolutionarily classified as a GH13_36 subfamily intermediary amylase. Recombinant Rbamy5 exhibited maximum activity toward amylose (384 ± 26 U·mg−1) over soluble starch (254 ± 3 U·mg−1), amylopectin (46.1 ± 2.6 U·mg−1) and pullulan (72.5 ± 0.41 U·mg−1) at 45 °C and pH 5.0. It was also able to degrade small substrates such as maltotriose (G3), maltotetraose (G4), and maltopentaose (G5) into maltose (G2). Despite lacking a specific N-terminal domain, Rbamy5 opened the cyclodextrin ring, which resembles those of neopullulanase. Moreover, it accumulated short α-(1 → 6)-branched maltooligosaccharides from soluble starch and maltosyl-β-cyclodextrin (G2-β-CD), while panose was solely derived from pullulan. These results suggest that Rbamy5 may have a role to provide branched maltooligosaccharides to stimulate the growth of beneficial microorganisms in the human intestine.

β-Glucosylglycerol (β-GG) and their derivatives have potential applications in food, cosmetics and the healthcare industry, including antitumor medications. In this study, β-GG and its unnatural glycosides were synthesized through the transglycosylation of two enzymes, Sulfolobus shibatae β-glycosidase (SSG) and Deinococcus geothermalis amylosucrase (DGAS). SSG catalyzed a transglycosylation reaction with glycerol as an acceptor and cellobiose as a donor to produce 56% of β-GGs [β-D-glucopyranosyl-(1→1/3)-D-glycerol and β-D-glucopyranosyl- (1→2)-D-glycerol]. In the second transglycosylation reaction, β-D-glucopyranosyl-(1 → 1/3)-Dglycerol was used as acceptor molecules of the DGAS reaction. As a result, 61% of α-Dglucopyranosyl-( 1→4)-β-D-glucopyranosyl-(1→1/3)-D-glycerol and 28% of α-D-maltopyranosyl- (1→4)-β-D-glucopyranosyl-(1→1/3)-D-glycerol were synthesized as unnatural glucosylglycerols. In conclusion, the combined enzymatic synthesis of the unnatural glycosides of β-GG was established. The synthesis of these unnatural glycosides may provide an opportunity to discover new applications in the biotechnological industry.

We have isolated and identified 72 bacterial strains from four bentonite samples collected at the mining areas located in Gyeongsangbuk-do, Republic of Korea, and measured their hydrolytic enzyme (α-amylase, protease, and cellulase) activities to identify the isolates with industrial-use potential. Most of the isolates belonged to the Bacillaceae, with minor portions being from the Paenibacillaceae, Micrococcaceae, and Bacillales Family XII at the family level. Of the strains isolated, 33 had extracellular α-amylase activity, 30 strains produced cellulase, and 35 strains produced protease. Strain MBLB1268, having the highest α-amylase activity, was identified as Bacillus siamensis (0.38 ± 0.06 U/ml). Bacillus tequilensis MBLB1223, isolated from Byi33-b, showed the highest cellulase activity (0.26 ± 0.04 U/ml), whereas Bacillus wiedmannii MBLB1197, isolated from Zdb130-b, exhibited the highest protease activity (54.99 ± 0.78 U/ml). These findings show that diverse bacteria of the Bacillaceae family adhere to and exist in bentonite and are potential sources of industrially useful hydrolytic enzymes.

Glycemic carbohydrates, such as starch and sucrose, are fully hydrolyzed into monosaccharides by mucosal α-glucosidases in the small intestine. In this study, we optimized the reaction conditions of mammalian mucosal α-glucosidases to digest various types of glycemic carbohydrates to determine their hydrolytic activity. The results clearly showed that mammalian mucosal α-glucosidases had different hydrolytic properties compared to fungal amyloglucosidase, which is commonly used in vitro assay to determine carbohydrate quality, on various sizes and α-linked carbohydrates. Furthermore, non-gelatinized and gelatinized starches from different botanical sources were differently hydrolyzed to glucose by the prepared solution of mammalian α-glucosidases and porcine pancreatic α-amylase. Thus, it is clearly suggested that the digestion of glycemic carbohydrates by the optimized reaction condition with mammalian mucosal α-glucosidases and pancreatic α-amylase can be applied to determine the carbohydrate quality and digestion properties as it is more reliable to human digestive enzymes compared to fungal or microbial α-glucosidases.

Isoquercitrin (IQ, quercetin-3-O-β-d-glucopyranoside) has diverse biological functions, such as anti-oxidant and anti-cancer activity, but its use is limited by poor solubility and bioavailability. Enzymatically modified IQ (EMIQ) is a mixture of transglycosylated IQs that have better solubility and bioavailability than do quercetin and IQ. Two different enzymes, cyclodextrin glucanotransferase (CGTase) and amylosucrase (ASase), have the transglycosylation activity to produce EMIQ. Both enzymes produce a variety of EMIQs including IQ, IQ-glucoside (IQ-G1), IQ-diglucoside (IQ-G2), and IQ-triglucoside (IQ-G3). ASase had a higher bioconversion yield from IQ to EMIQ (97.6%) than did CGTase (76.8%). In addition, the yield of IQ-G3, which was the most bioavailable form, was higher with ASase (46%) than with CGTases (8%). Taken together, these results suggest that ASase can be used to synthesize EMIQ in a simple and specific process.

Amylosucrase (ASase; EC 2.4.1.4), a versatile enzyme, exhibits three characteristic activities: hydrolysis, isomerization, and transglycosylation. In this study, a novel ASase derived from Deinococcus wulumuquiensis (DWAS) was identified and expressed in Escherichia coli. The optimal reaction temperature and pH for the sucrose hydrolysis activity of DWAS were determined to be 45 °C and 9.0, respectively. DWAS displays relatively high thermostability compared with other ASases, as demonstrated by half-life of 96.7 and 4.7 min at 50 °C and 55 °C, respectively. DWAS fused with 6×His was successfully purified to apparent homogeneity with a molecular mass of approximately 72 kDa by Ni-NTA affinity chromatography and confirmed by SDS-PAGE. DWAS transglycosylation activity can be used to modify isovitexin, a representative flavone C-glucoside contained in buckwheat sprouts to increase its limited bioavailability, which is due to its low absorption rate and unstable structure in the human body. Using isovitexin as a substrate, the major transglycosylation product of DWAS was found to be isovitexin monoglucoside. The comparison of transglycosylation reaction products of DWAS with those of other ASases derived from Deinococcus species revealed that the low sequence homology of loop 8 in ASases may affect the acceptor specificity of ASases and result in a distinctive acceptor specificity of DWAS.

Carotenoids, which have biologically beneficial effects and occur naturally in microorganisms and plants, are pigments widely applied in the food, cosmetics and pharmaceutical industries. The compound 4,4'-diaponeurosporene is a C

Agricultural water is closely linked to surface and ground water as well as soil, hence, ensuring its safety is an important endeavor. We used the &ldquo, quick, easy, cheap, effective, rugged, and safe&rdquo, (QuEChERS) method to analyze multi-residue pesticides in agricultural water by using a combined-sorbent-based clean-up procedure. Among the various sorbents examined, clean-up using ENVI-Carb combined with a primary secondary amine sorbent delivered the highest recovery of multi-residue pesticides (&gt, 93.9%). While the developed method showed satisfactory linearity (R2 &gt, 0.9991), precision, and specificity, recovery was low for pyrazolate (29.1%) and thidiazuron (59.2%). The limits of detection and quantification for the 55 pesticides targeted in this study were in 0.02&ndash, 3.0 &mu, g L&minus, 1 and 0.1&ndash, 9.9 &mu, 1, respectively. The developed method was used to identify and quantify multi-residue pesticides during sample analysis. The results suggest that the QuEChERS method employing a combination of ENVI-Carb and another sorbent can be applied for the effective analysis of multi-residue pesticides in agricultural water.

The article “Versatile biotechnological applications of amylosucrase, a novel glucosyltransferase”, written by Dong-Ho Seo, Sang-Ho Yoo, Seung-Jun Choi, Young-Rok Kim and Cheon-Seok Park, was originally published Online First without Open Access. After publication in volume 29, issue 1, page 1–16 the author decided to opt for Open Choice and to make the article an Open Access publication. Therefore, the copyright of the article has been changed to © The Author(s) 2020 and the article is forthwith distributed under the terms of the Creative Commons Attribution 4.0 International License ( http://creativecommons.org/licenses/by/4.0/ ), which permits use, duplication, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Amylosucrase (ASase, E.C. 2.4.1.4) is capable of efficient glucose transfer from sucrose, acting as the sole donor molecule, to various functional acceptor compounds, such as polyphenols and flavonoids. An ASase variant from

Carotenoids are group of colored terpenoids with antioxidant properties and widespread in nature including in microorganisms. Lactobacillus plantarum subsp. plantarum KCCP11226 was previously isolated from kimchi, while exhibiting the production of 4,4′-diaponeurosporene as a C(30) carotenoid. In this study, full genome sequencing of the strain KCCP11226 was performed. Genome analysis revealed that the dehydrosqualene synthase (crtM) and dehydrosqualene desaturase (crtN) genes, which are major genes for biosynthesis of 4,4′-diaponeurosporene, were shown to act as an operon in most L. plantarum strains, but they were uncommon in other Lactobacillus species. In vitro experiments revealed that the production of 4,4′-diaponeurosporene was greatly increased by oxidative stress. In this situation, mRNA expressions of crtN and crtM were also significantly increased. In conclusion, genome analysis of L. plantarum subsp. plantarum KCCP11226 suggested the presence of a well-conserved C(30) carotenoid biosynthetic pathway that includes the crtM–crtN operon. The genomic information on L. plantarum subsp. plantarum KCCP11226 could further elucidate the functions of genes involved in isoprenoid biosynthetic pathway, especially in C(30) carotenoid biosynthesis. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13205-020-2149-y) contains supplementary material, which is available to authorized users.

Amylosucrase (ASase) is α-glucan-producing enzyme. Four putative ASase genes (bdas, blas, bpas, and btas) were cloned from Bifidobacterium sp. and expressed in Escherichia coli. All ASases from Bifidobacterium sp. (BAS) displayed typical ASase properties with slightly different characteristics. Among the BASs studied, BdAS and BpAS showed maximal enzyme activities at 35 and 30 °C, respectively, whereas BlAS and BtAS were maximally active at higher temperatures, i.e., 45 and 50 °C, respectively. BpAS exhibited optimum pH under slightly basic conditions (pH 8.0), while BdAS, BlAS, and BtAS preferred weakly acidic conditions (pH 5.0–6.0). All BASs showed higher isomerization activities. Particularly, BlAS produced more trehalulose than turanose. Although polymerization was the highest for BtAS, BtAS synthesized α-1, 4-glucans with a lower degree of polymerization than that of the other BASs. The versatile properties of the BASs described could contribute to the efficient production of highly valuable biomaterials for the agriculture, food, and pharmaceutical industries.

Resistant starch (RS) is an important food source from which gut bacteria produce short chain fatty acids, which have beneficial effects for human health. The Bifidobacterium adolescentis P2P3, a human gut bacterium possessing a strong RS-degrading activity, was isolated from a healthy Korean adult male. In vitro experiments showed that this bacterium could utilize approximately 63% of high amylose corn starch after forming RS granule clusters. Here we provide the first complete set of genomic information on RS-degrading B. adolescentis P2P3. The genome of B. adolescentis P2P3 consists of one chromosome (2,202,982 bp) with high GC content (59.4%). Analysis of the protein-coding genes revealed that at least nineteen of the starch degradation-related enzymes were present in the genome. Among those, five genes evidently possess carbohydrate-binding domains, which are presumed to be involved in efficient RS decomposition. The complete set of genomic information on B. adolescentis P2P3 could provide an understanding of the role of RS-degrading gut bacteria and its RS degradation mechanism.

Isoflavones in soybeans are well-known phytoestrogens. Soy isoflavones present in conjugated forms are converted to aglycone forms during processing and storage. Isoflavone aglycones (IFAs) of soybeans in human diets have poor solubility in water, resulting in low bioavailability and bioactivity. Enzyme-mediated glycosylation is an efficient and environmentally friendly way to modify the physicochemical properties of soy IFAs. In this study, we determined the optimal reaction conditions for Deinococcus geothermalis amylosucrase-mediated α-1,4 glycosylation of IFA-rich soybean extract to improve the bioaccessibility of IFAs. The conversion yields of soy IFAs were in decreasing order as follows: genistein &gt, daidzein &gt, glycitein. An enzyme quantity of 5 U and donor:acceptor ratios of 1000:1 (glycitein) and 400:1 (daidzein and genistein) resulted in high conversion yield (average 95.7%). These optimal reaction conditions for transglycosylation can be used to obtain transglycosylated IFA-rich functional ingredients from soybeans.

Effects of stirring during gelatinization and shaking during hydrolysis on physicochemical properties of short-chain glucan aggregates (SCGA) were investigated. Both stirring and shaking improved SCGA yield, and also affected the formation and crystallization kinetics of SCGA. Without stirring and shaking, slow SCGA forming rate, large size (∼1.32 μm), high relative crystallinity (RC), high endothermic onset temperature, and high melting enthalpy (ΔH) were observed. Stirring and shaking yielded the fastest SCGA formation and crystallization rates as well as the smallest SCGA size (∼0.57 μm). Small SCGA had a low RC and low heat stability, possibly due to the presence of imperfections and low double helix content. Formation yield was negatively correlated with size, ΔH, RC, and the resistant starch content of SCGA. The highest correlations were observed between ΔH and RC. This study proves that the SCGA characteristics can easily be controlled by stirring during gelatinization and shaking during enzymatic hydrolysis.

Branch-chain elongated starches can be synthesized by amylosucrase (AS). In this study, potato starches with different branch-chain length were produced using the temperature-dependent elongation property of AS from Deinococcus geothermalis (DGAS). Decreasing the reaction temperature led to a significant rise in the length of the branch-chains, in addition to amylose content. As branch-chain length increased, B-type crystal structure increased significantly alongside it, and the thermal transitions were enhanced, suggesting that the crystalline structure was further stabilized. In addition, a decrease in solubility and swelling power was observed, whereas the gelatinization temperatures and peak viscosities increased accordingly. With respect to digestive properties, a remarkable rise in slowly digestible starch (0–19.8%) and resistant starch (38.2%–62.2%) contents was observed, along with an enhanced resistance to mammalian mucosal α-glucosidase. In conclusion, enzymatic modification by DGAS might be an innovative method to regulate the physicochemical and digestive properties of starches.

1-Deoxynojirimycin (1-DNJ) is an α-glucosidase inhibitor that is used for the treatment of type 2 diabetes. In this study, we isolated Bacillus methylotrophicus K26 with α-glucosidase inhibition (AGI) activity from Korean fermented soybean paste (Doenjang) and confirmed that the genome harbored the DNJ biosynthesis genes including gabT1, yktc1, and gutB1 by PCR screening, while 1-DNJ production was confirmed by ultra-performance liquid chromatography–quadrupole time-of-flight–mass spectrometry. To increase 1-DNJ production by B. methylotrophicus K26, culture conditions were optimized with one-factor-ata- time (OFAT) and response surface methodology (RSM) approaches. Screen of 11 carbon and 9 nitrogen sources by the OFAT method identified sucrose and yeast extract as optimal culture components. Sucrose concentration (X1), yeast extract concentration (X2), and culture temperature (X3) were selected as independent variables for central composite design. The coefficient of determination (R2) for the model was 0.927, and the probability value of the regression model was highly significant. RSM predicted the optimal conditions for 1-DNJ production by B. methylotrophicus K26 as sucrose and yeast extract concentrations of 4.61% and 7.03%, respectively, at a temperature of 34°C. Under these conditions, AGI activity was experimentally measured as 89.3%, which was close to the predicted value of 91.9%.