Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Huiying Luo is active.

Publication


Featured researches published by Huiying Luo.


Applied and Environmental Microbiology | 2009

Diversity of Beta-Propeller Phytase Genes in the Intestinal Contents of Grass Carp Provides Insight into the Release of Major Phosphorus from Phytate in Nature

Huoqing Huang; Pengjun Shi; Yaru Wang; Huiying Luo; Na Shao; Guozeng Wang; Peilong Yang; Bin Yao

ABSTRACT Phytate is the most abundant organic phosphorus compound in nature, and microbial mineralization of phytate by phytase is a key process for phosphorus recycling in the biosphere. In the present study, beta-propeller phytase (BPP) gene fragments were readily amplified from the intestinal contents of grass carp (Ctenopharyngodon idellus) directly or from phytate-degrading isolates from the same source, confirming the widespread occurrence of BPP in aquatic communities. The amounts of sequences collected using these two methods differed (88 distinct genes versus 10 isolates), but the sequences showed the same general topology based on phylogenetic analysis. All of the sequences fell in five clusters and were distinct from those of Anabaena, Gloeobacter, Streptomyces, Flavobacterium, Prosthecochloris, and Desulfuromonas, which have never been found in the grass carp intestine. Analysis of the microbial diversity by denaturing gradient gel electrophoresis demonstrated that unculturable bacteria were dominant bacteria in the grass carp intestine and thus the predominant phytate-degrading organisms. The predominant cultured species corresponding to the phytate-degrading isolates, Pseudomonas, Bacillus and Shewanella species, might be the main source of known BPPs. A phytase from Brevundimonas was first obtained from cultured species. Combining our results with Lim et al.s inference that phytate-mineralizing bacteria are widely distributed and highly diverse in nature (B. L. Lim, P. Yeung, C. Cheng, and J. E. Hill, ISME J. 1:321-330, 2007), we concluded that BPP is the major phytate-degrading enzyme in nature, that most of this enzyme might originate from unculturable bacteria, and that the distribution of BPP may be related to the type of niche. To our knowledge, this is the first study to experimentally estimate BPP diversity in situ.


Food Chemistry | 2014

Two xylose-tolerant GH43 bifunctional β-xylosidase/α-arabinosidases and one GH11 xylanase from Humicola insolens and their synergy in the degradation of xylan

Xinzhuo Yang; Pengjun Shi; Huoqing Huang; Huiying Luo; Yaru Wang; Wei Zhang; Bin Yao

Two β-xylosidases of family 43 (Xyl43A and Xyl43B) and one xylanase of family 11 (Xyn11A) were identified from the genome sequence of Humicola insolens Y1, and their gene products were successfully expressed in heterologous hosts. The optimal activities of the purified Xyl43A, Xyl43B, and Xyn11A were found at pH 6.5-7.0 and 50-60 °C. They were stable over a pH range of 5.0-10.0 and temperatures of 50 °C and below. Xyl43A and Xyl43B had the activities of β-xylosidase, α-arabinosidase and xylanase, and showed xylose tolerance up to 79 and 292 mM, respectively. Xyn11A and Xyl43A or Xyl43B showed significant synergistic effects on the degradation of various xylans, releasing more reduced sugars (up to 1.29 folds) by simultaneous or sequential addition. This study provides several enzymes for synergistic degradation of xylan and contributes to the formulation of optimised enzyme mixtures for the efficient hydrolysis of plant biomass.


Enzyme and Microbial Technology | 2010

A xylanase with broad pH and temperature adaptability from Streptomyces megasporus DSM 41476, and its potential application in brewing industry.

Zhenhua Qiu; Pengjun Shi; Huiying Luo; Yingguo Bai; Tiezheng Yuan; Peilong Yang; Suchun Liu; Bin Yao

A xylanase gene, xynAM6, was isolated from the genomic DNA library of Streptomyces megasporus DSM 41476 using colony PCR screening method. The 1440-bp full-length gene encodes a 479-amino acid peptide consisting of a putative signal peptide of 36 residues, a family 10 glycoside hydrolase domain and a family 2 carbohydrate-binding module. The mature peptide of xynAM6 was successfully expressed in Pichia pastoris GS115. The optimal pH and temperature were pH 5.5 and 70°C, respectively. The enzyme showed broad temperature adaptability (>60% of the maximum activity at 50-80°C), had good thermostability at 60°C and 70°C, remained stable at pH 4.0-11.0, and was resistant to most proteases. The Km and Vmax values for oat spelt xylan were 1.68mgml(-1) and 436.76μmolmin(-1)mg(-1), respectively, and 2.33mgml(-1) and 406.93μmolmin(-1)mg(-1) for birchwood xylan, respectively. The hydrolysis products of XYNAM6 were mainly xylose and xylobiose. Addition of XYNAM6 (80U) to the brewery mash significantly reduced the filtration rate and viscosity by 36.33% and 35.51%, respectively. These favorable properties probably make XYNAM6 a good candidate for application in brewing industry.


Bioresource Technology | 2011

A novel cold-active xylanase gene from the environmental DNA of goat rumen contents: Direct cloning, expression and enzyme characterization

Guozeng Wang; Huiying Luo; Yaru Wang; Huoqing Huang; Pengjun Shi; Peilong Yang; Kun Meng; Yingguo Bai; Bin Yao

A xylanase-coding gene, xynGR40, was cloned directly from the environmental DNA of goat rumen contents and expressed in Escherichia coli BL21 (DE3). The 1446-bp full-length gene encodes a 481-residue polypeptide (XynGR40) containing a catalytic domain belonging to glycosyl hydrolase (GH) family 10. Phylogenetic analysis indicated that XynGR40 was closely related with microbial xylanases of gastrointestinal source. Purified recombinant XynGR40 exhibited high activity at low temperatures, and remained active (∼10% of the activity) even at 0°C. The optimal temperature of XynGR40 was 30°C, much lower than other xylanases from rumen. Compared with mesophilic and thermophilic counterparts, XynGR40 had fewer hydrogen bonds and salt bridges, and lengthened loops in the catalytic domain. The enzyme also had relatively better stability at mesophilic temperatures and a higher catalytic efficiency than other known GH 10 cold active xylanases. These properties suggest that XynGR40 is a novel cold active xylanase and has great potential for basic research and industrial applications.


Bioresource Technology | 2010

An α-galactosidase from an acidophilic Bispora sp. MEY-1 strain acts synergistically with β-mannanase

Hui Wang; Huiying Luo; Jiang Li; Yingguo Bai; Huoqing Huang; Pengjun Shi; Yunliu Fan; Bin Yao

An alpha-galactosidase gene (AgalB) was cloned from the acidophilic fungus Bispora sp. MEY-1 and expressed in Pichia pastoris. The deduced amino acid sequence showed highest identity (35%) to the alpha-galactosidase from Penicillium simplicissimum, belonging to the glycosyl hydrolase family 27. The purified recombinant alpha-galactosidase (r-AgalB) exhibited optimal activity at pH 3.5 and 55 degrees C, was stable at pH 2.2-8.0, and showed higher hydrolytic activity towards galactomannan polysaccharides (guar gum and locust bean gum) than toward small galacto-oligosaccharides (melibiose, raffinose and stachyose). A synergistic (3-fold) increase in guar gum hydrolysis was observed when beta-mannanase Man5A from Bispora sp. MEY-1 and r-AgalB were combined. Further, an increase in the reaction time from 5h to 12h or increase of the temperature from 37 degrees C to 55 degrees C enhanced guar gum degradation by the enzyme combination. These properties make r-AgalB a good candidate for extensive application in the pulp/paper, food, and feed industries.


Applied and Environmental Microbiology | 2014

Thermostability Improvement of a Streptomyces Xylanase by Introducing Proline and Glutamic Acid Residues

Kun Wang; Huiying Luo; Jian Tian; Ossi Turunen; Huoqing Huang; Pengjun Shi; Huifang Hua; Caihong Wang; Shuanghe Wang; Bin Yao

ABSTRACT Protein engineering is commonly used to improve the robustness of enzymes for activity and stability at high temperatures. In this study, we identified four residues expected to affect the thermostability of Streptomyces sp. strain S9 xylanase XynAS9 through multiple-sequence analysis (MSA) and molecular dynamic simulations (MDS). Site-directed mutagenesis was employed to construct five mutants by replacing these residues with proline or glutamic acid (V81P, G82E, V81P/G82E, D185P/S186E, and V81P/G82E/D185P/S186E), and the mutant and wild-type enzymes were expressed in Pichia pastoris. Compared to the wild-type XynAS9, all five mutant enzymes showed improved thermal properties. The activity and stability assays, including circular dichroism and differential scanning calorimetry, showed that the mutations at positions 81 and 82 increased the thermal performance more than the mutations at positions 185 and 186. The mutants with combined substitutions (V81P/G82E and V81P/G82E/D185P/S186E) showed the most pronounced shifts in temperature optima, about 17°C upward, and their half-lives for thermal inactivation at 70°C and melting temperatures were increased by >9 times and approximately 7.0°C, respectively. The mutation combination of V81P and G82E in adjacent positions more than doubled the effect of single mutations. Both mutation regions were at the end of long secondary-structure elements and probably rigidified the local structure. MDS indicated that a long loop region after positions 81 and 82 located at the end of the inner β-barrel was prone to unfold. The rigidified main chain and filling of a groove by the mutations on the bottom of the active site canyon may stabilize the mutants and thus improve their thermostability.


Bioresource Technology | 2013

Characterization of three novel thermophilic xylanases from Humicola insolens Y1 with application potentials in the brewing industry.

Yanlong Du; Pengjun Shi; Huoqing Huang; Xiu Zhang; Huiying Luo; Yaru Wang; Bin Yao

Three xylanase genes (xynA, xynB, xynC) of glycosyl hydrolase family 10 were identified in Humicola insolens Y1. The deduced protein sequences showed the highest identity of ⩽83% to known fungal xylanases and of ⩽38% with each other. Recombinant XynA-C produced in Pichia pastoris showed optimal activities at pH 6.0-7.0 and at high temperature (70-80°C), and exhibited good stability over a broad pH range and temperatures at 60°C. The gene xynC produced by H. insolens Y1 (named XynW) was similar in enzyme properties with XynC expressed by Pichia. XynA exhibited better alkaline adaptation and thermostability, and had higher catalytic efficiency and wider substrate specificity. Under simulated mashing conditions, addition of XynA-C showed better performance on filtration acceleration (37.4%) and viscosity reduction (13.5%) than Ultraflo from Novozyme. Thus the three xylanases represent good candidates for application in the brewing industry.


Journal of Agricultural and Food Chemistry | 2010

An Acidophilic and Acid-Stable β-Mannanase from Phialophora sp. P13 with High Mannan Hydrolysis Activity under Simulated Gastric Conditions

Junqi Zhao; Pengjun Shi; Huiying Luo; Peilong Yang; Heng Zhao; Yingguo Bai; Huoqing Huang; Hui Wang; Bin Yao

A beta-mannanase gene, man5AP13, was cloned from Phialophora sp. P13 and expressed in Pichia pastoris. The deduced amino acid sequence of the mature enzyme, MAN5AP13, had highest identity (53%) with the glycoside hydrolase family 5 beta-mannanase from Bispora sp. MEY-1. The purified recombinant beta-mannanase was acidophilic and acid stable, exhibiting maximal activity at pH 1.5 and retaining >60% of the initial activity over the pH range 1.5-7.0. The optimum temperature was 60 degrees C. The specific activity, K(m) and V(max) for locust bean gum substrate were 851 U/mg, 2.5 mg/mL, and 1667.7 U/min.mg, respectively. The enzyme had excellent activity and stability under simulated gastric conditions, and the released reducing sugar of locust bean gum was significantly enhanced by one-fold in simulated gastric fluid containing pepsin in contrast to that without pepsin. All these properties make MAN5AP13 a potential additive for use in the food and feed industries.


Applied Microbiology and Biotechnology | 2010

Molecular detection and diversity of xylanase genes in alpine tundra soil

Guozeng Wang; Yaru Wang; Peilong Yang; Huiying Luo; Huoqing Huang; Pengjun Shi; Kun Meng; Bin Yao

Xylan is a major polysaccharide in plant cell walls, and its degradation is mainly conducted by microbial xylanases in nature. To explore the xylanase diversity in the environment, two sets of degenerate primers were designed based on the microbial xylanase sequences in Pfam database of glycosyl hydrolase (GH) family 10 and 11 and were used to amplify objective gene fragments directly from the alpine tundra soil DNA of the Tianshan Mountains, China. Ninety-six distinct GH 10 and 31 GH 11 xylanase gene fragments were retrieved, and most of them have low identities with known sequences in GenBank. Based on phylogenetic analysis, all of the GH 10 xylanase sequences fell into six clusters and were related to xylanases from Actinobacteria, Proteobacteria, Verrucomicrobia, Bacteroidetes, Firmicutes, and Acidobacteria. Three clusters of GH 11 xylanase sequences were established, and two of them were related with enzymes from fungi. These results indicated the diversity of xylanase genes in this cold environment. Four xylanolytic strains were isolated from the soil, and GH 10 xylanase gene fragments were cloned using the same primers. A full-length gene was obtained and expressed in Escherichia coli, and the recombinant enzyme showed some cold-related characteristics. Our study provides an efficient molecular approach to study xylanase in complex environments and casts an insight into the diversity and distribution of xylanases in a cold environment, which is very meaningful to understand their roles in xylan degradation in nature.


Food Chemistry | 2013

High-yield production of a low-temperature-active polygalacturonase for papaya juice clarification

Tao Tu; Kun Meng; Yingguo Bai; Pengjun Shi; Huiying Luo; Yaru Wang; Peilong Yang; Yuhong Zhang; Wei Zhang; Bin Yao

A novel endo-polygalacturonase (endo-PG I) from Achaetomium sp. Xz8 was identified, overexpressed in Pichia pastoris, and characterized in this report. Recombinant endo-PG I is distinguished from other enzyme counterparts by its high activity towards polygalacturonic acid (49,934 U/ml) and high yield in the 15-l fermentor (2.13 g/l). It exhibits optimal activity at 45 °C and remained active over a broad temperature range of 0-80 °C. Distinct from most fungal polygalacturonases that have acidic pH optima, endo-PG I is optimally active at pH 6, similar to the pH of fresh papaya juice (5.7). Endo-PG I alone reduced the viscosity of papaya juice by 17.6%, and increased its transmittance by 59.1%. When combined with a commercial pectin methylesterase, it showed much higher efficiency with a synergy degree of more than 1.25. All these favourable enzymatic properties make endo-PG I attractive for potential applications in the juice industry.

Collaboration


Dive into the Huiying Luo's collaboration.

Top Co-Authors

Avatar

Huoqing Huang

National University of Kaohsiung

View shared research outputs
Top Co-Authors

Avatar

Bin Yao

Northeast Agricultural University

View shared research outputs
Top Co-Authors

Avatar

Yaru Wang

National University of Singapore

View shared research outputs
Top Co-Authors

Avatar

Rui Ma

Biotechnology Institute

View shared research outputs
Top Co-Authors

Avatar

Xiaoyu Wang

University of Minnesota

View shared research outputs
Top Co-Authors

Avatar

Yunliu Fan

Biotechnology Institute

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Zhongyuan Li

Tianjin University of Science and Technology

View shared research outputs
Top Co-Authors

Avatar

Fei Zheng

University of Minnesota

View shared research outputs
Top Co-Authors

Avatar

Wei Zhang

Biotechnology Institute

View shared research outputs
Researchain Logo
Decentralizing Knowledge