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1.
Biotechnol Bioeng ; 121(7): 2163-2174, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38595326

RESUMO

Pathogenic bacterial membrane proteins (MPs) are a class of vaccine and antibiotic development targets with widespread clinical application. However, the inherent hydrophobicity of MPs poses a challenge to fold correctly in living cells. Herein, we present a comprehensive method to improve the soluble form of MP antigen by rationally designing multi-epitope chimeric antigen (ChA) and screening two classes of protein-assisting folding element. The study uses a homologous protein antigen as a functional scaffold to generate a ChA possessing four epitopes from transferrin-binding protein A of Glaesserella parasuis. Our engineered strain, which co-expresses P17 tagged-ChA and endogenous chaperones groEL-ES, yields a 0.346 g/L highly soluble ChA with the property of HPS-positive serum reaction. Moreover, the protein titer of ChA reaches 4.27 g/L with >90% soluble proportion in 5-L bioreactor, which is the highest titer reported so far. The results highlight a timely approach to design and improve the soluble expression of MP antigen in industrially viable applications.


Assuntos
Antígenos de Bactérias , Antígenos de Bactérias/genética , Antígenos de Bactérias/imunologia , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/metabolismo , Reatores Biológicos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/química , Escherichia coli/genética , Escherichia coli/metabolismo , Clostridiales/genética , Clostridiales/metabolismo , Solubilidade
2.
Appl Microbiol Biotechnol ; 108(1): 54, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38175240

RESUMO

Hyaluronidases catalyze the degradation of hyaluronan (HA), which is finding rising applications in medicine, cosmetic, and food industries. Recombinant expression of hyaluronidases in microbial hosts has been given special attention as a sustainable way to substitute animal tissue-derived hyaluronidases. In this study, we focused on optimizing the secretion of hyaluronidase from Homo sapiens in Pichia pastoris by secretion pathway engineering. The recombinant hyaluronidase was first expressed under the control of a constitutive promoter PGCW14. Then, two endoplasmic reticulum-related secretory pathways were engineered to improve the secretion capability of the recombinant strain. Signal peptide optimization suggested redirecting the protein into co-translational translocation using the ost1-proα signal sequence improved the secretion level by 20%. Enhancing the co-translational translocation by overexpressing signal recognition particle components further enhanced the secretory capability by 48%. Then, activating the unfolded protein response by overexpressing a transcriptional factor ScHac1p led to a secreted hyaluronidase activity of 4.06 U/mL, which was 2.1-fold higher than the original strain. Finally, fed-batch fermentation elevated the production to 19.82 U/mL. The combined engineering strategy described here could be applied to enhance the secretion capability of other proteins in yeast hosts. KEY POINTS: • Improving protein secretion by enhancing co-translational translocation in P. pastoris was reported for the first time. • Overexpressing Hac1p homologous from different origins improved the rhPH-20 secretion. • A 4.9-fold increase in rhPH-20 secretion was achieved after fermentation optimization and fed-batch fermentation.


Assuntos
Hialuronoglucosaminidase , Resposta a Proteínas não Dobradas , Animais , Humanos , Hialuronoglucosaminidase/genética , Transporte Proteico , Retículo Endoplasmático
3.
Metab Eng ; 78: 99-114, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37244368

RESUMO

Solubility and folding stability are key concerns for difficult-to-express proteins (DEPs) restricted by amino acid sequences and superarchitecture, resolved by the precise distribution of amino acids and molecular interactions as well as the assistance of the expression system. Therefore, an increasing number of tools are available to achieve efficient expression of DEPs, including directed evolution, solubilization partners, chaperones, and affluent expression hosts, among others. Furthermore, genome editing tools, such as transposons and CRISPR Cas9/dCas9, have been developed and expanded to construct engineered expression hosts capable of efficient expression ability of soluble proteins. Accounting for the accumulated knowledge of the pivotal factors in the solubility and folding stability of proteins, this review focuses on advanced technologies and tools of protein engineering, protein quality control systems, and the redesign of expression platforms in prokaryotic expression systems, as well as advances of the cell-free expression technologies for membrane proteins production.


Assuntos
Sistemas CRISPR-Cas , Biologia Sintética , Edição de Genes , Engenharia de Proteínas , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo
4.
Appl Environ Microbiol ; 89(6): e0022023, 2023 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-37191513

RESUMO

Nitrilase can catalyze nitrile compounds to generate corresponding carboxylic acids. Nitrilases as promiscuous enzymes can catalyze a variety of nitrile substrates, such as aliphatic nitriles, aromatic nitriles, etc. However, researchers tend to prefer enzymes with high substrate specificity and high catalytic efficiency. In this study, we developed an active pocket remodeling (ALF-scanning) based on modulating the geometry of the nitrilase active pocket to alter substrate preference and improve catalytic efficiency. Using this strategy, combined with site-directed saturation mutagenesis, we successfully obtained 4 mutants with strong aromatic nitrile preference and high catalytic activity, W170G, V198L, M197F, and F202M, respectively. To explore the synergistic relationship of these 4 mutations, we constructed 6 double-combination mutants and 4 triple-combination mutants. By combining mutations, we obtained the synergistically enhanced mutant V198L/W170G, which has a significant preference for aromatic nitrile substrates. Compared with the wild type, its specific activities for 4 aromatic nitrile substrates are increased to 11.10-, 12.10-, 26.25-, and 2.55-fold, respectively. By mechanistic dissection, we found that V198L/W170G introduced a stronger substrate-residue π-alkyl interaction in the active pocket and obtained a larger substrate cavity (225.66 Å3 to 307.58 Å3), making aromatic nitrile substrates more accessible to be catalyzed by the active center. Finally, we conducted experiments to rationally design the substrate preference of 3 other nitrilases based on the substrate preference mechanism and also obtained the corresponding aromatic nitrile substrate preference mutants of these three nitrilases and these mutants with greatly improved catalytic efficiency. Notably, the substrate range of SmNit is widened. IMPORTANCE In this study, the active pocket was largely remodeled based on the ALF-scanning strategy we developed. It is believed that ALF-scanning not only could be employed for substrate preference modification but might also play a role in protein engineering of other enzymatic properties, such as substrate region selectivity and substrate spectrum. In addition, the mechanism of aromatic nitrile substrate adaptation we found is widely applicable to other nitrilases in nature. To a large extent, it could provide a theoretical basis for the rational design of other industrial enzymes.


Assuntos
Aminoidrolases , Nitrilas , Aminoidrolases/genética , Aminoidrolases/metabolismo , Catálise , Engenharia de Proteínas , Especificidade por Substrato
5.
Crit Rev Food Sci Nutr ; 63(21): 5268-5289, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-34907819

RESUMO

Collagen is a kind of high macromolecular protein with unique tissue distribution and distinctive functions in the body. At present, most collagen products are extracted from the tissues and organs of mammals or marine fish. However, this method exhibits several disadvantages, including low efficiency and serious waste generation, which makes it difficult to meet the current market demand. With the rapid development of synthetic biology and the deepening of high-density fermentation technology, the collagen preparation by biosynthesis strategy emerges as the times require. Co-expression with the proline hydroxylase gene can solve the problem of non-hydroxylated collagen, but the yield may be affected. Therefore, improving the expression through molecular modification and dynamic regulation of synthesis is an entry point for future research. Due to the defects in certain properties of the natural collagen, modification of properties would be benefit for meeting the requirements of practical application. In this paper, in-depth investigations on recombinant expression, fermentation, and modification studies of collagen are conducted. Also, it summarizes the research progress of collagen in food, medicine, and beauty industry in recent years. Furthermore, the future development trend and application prospect of collagen are discussed, which would provide guidance for its preparation and application.


Assuntos
Colágeno , Mamíferos , Animais , Fermentação , Colágeno/genética , Mamíferos/metabolismo
6.
Appl Microbiol Biotechnol ; 107(15): 4759-4775, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37347262

RESUMO

Nicotinamide mononucleotide (NMN), a naturally occurring biologically active nucleotide, mainly functions via mediating the biosynthesis of NAD+. In recent years, its excellent pharmacological activities including anti-aging, treating neurodegenerative diseases, and protecting the heart have attracted increasing attention from scholars and entrepreneurs for production of a wide range of formulations, including functional food ingredients, health care products, active pharmaceuticals, and pharmaceutical intermediates. Presently, the synthesis methods of NMN mainly include two categories: chemical synthesis and biosynthesis. With the development of biocatalyst engineering and synthetic biology strategies, bio-preparation has proven to be efficient, economical, and sustainable methods. This review summarizes the chemical synthesis and biosynthetic pathways of NMN and provides an in-depth investigation on the mining and modification of enzyme resources during NMN biosynthesis, as well as the screening of hosts and optimization of chassis cells via metabolic engineering, which provide effective strategies for efficient production of NMN. In addition, an overview of the significant physiological functions and activities of NMN is elaborated. Finally, future research on technical approaches to further enhance NMN synthesis and strengthen clinical studies of NMN are prospected, which would lay the foundation for further promoting the application of NMN in nutrition, healthy food, and medicine in the future. KEY POINTS: • NMN supplementation effectively increases the level of NAD+. • The chemical and biological synthesis of NMN are comprehensively reviewed. • The impact of NMN on the treatment of various diseases is summarized.


Assuntos
NAD , Mononucleotídeo de Nicotinamida , Humanos , Mononucleotídeo de Nicotinamida/metabolismo , Mononucleotídeo de Nicotinamida/farmacologia , Mononucleotídeo de Nicotinamida/uso terapêutico , NAD/metabolismo , Envelhecimento , Tecnologia
7.
Appl Microbiol Biotechnol ; 106(7): 2349-2366, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35347378

RESUMO

Keratin is a kind of natural polymer that is abundant in feathers, wool, and hair. Being one of the natural biomolecules, keratin has excellent biological activity, biocompatibility, biodegradability, favorable material mechanical properties, and natural abundance, which exhibit significant biological and biomedical application potentials. At present, the strategies commonly used for preparing keratin from hair, feathers, wool, etc. include physical, chemical, and enzymatic methods. The present article mainly reviews the structure, classification, preparation methods, and the main biological applications of keratin, and these applications cover wound healing, hemostasis, targeted release of tissue engineering drugs, and so on. It is expected to lay the foundations for its future in-depth investigations and wide applications of keratin biomaterials. KEY POINTS: • There are several pathways to prepare biologically active keratin from wool, feathers, and human hair, etc • Promoting blood coagulation by keratin is related to the adhesion and activation of platelets and the aggregation of fibrin • The biological applications of keratin, including wound healing and tissue engineering, are summarized.


Assuntos
Materiais Biocompatíveis , Queratinas , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Humanos , Queratinas/química , Engenharia Tecidual , Lã/química , Cicatrização
8.
Appl Microbiol Biotechnol ; 106(18): 5893-5912, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36040488

RESUMO

Pichia pastoris has been recognized as an important platform for the production of various heterologous proteins in recent years. The strong promoter AOX1, induced by methanol, with the help of the α-pre-pro signal sequence, can lead to a high expression level of extracellular protein. However, this combination was not always efficient, as protein secretion in P. pastoris involves numerous procedures mediated by several cellular proteins, including folding assisted by endoplasmic reticulum (ER) molecular chaperones, degradation through ubiquitination, and an efficient vesicular transport system. Efficient protein expression requires the cooperation of various intracellular pathways. This article summarizes the process of protein secretion, modification, and transportation in P. pastoris. In addition, the roles played by the key proteins in these processes and the corresponding co-expression effects are also listed. It is expected to lay the foundation for the industrial protein production of P. pastoris. KEY POINTS: • Mechanisms of chaperones in protein folding and their co-expression effects are summarized. • Protein glycosylation modifications are comprehensively reviewed. • Current dilemmas in the overall protein secretion pathway of Pichia pastoris and corresponding solutions are demonstrated.


Assuntos
Pichia , Saccharomycetales , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo , Pichia/genética , Pichia/metabolismo , Engenharia de Proteínas , Proteômica , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Saccharomycetales/metabolismo
9.
Crit Rev Biotechnol ; 41(8): 1257-1278, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33985392

RESUMO

Owing to their numerous nutritional and bioactive functions, phospholipids (PLs), which are major components of biological membranes in all living organisms, have been widely applied as nutraceuticals, food supplements, and cosmetic ingredients. To date, PLs are extracted solely from soybean or egg yolk, despite the diverse market demands and high cost, owing to a tedious and inefficient manufacturing process. A microbial-based manufacturing process, specifically phospholipase D (PLD)-based biocatalysis and biotransformation process for PLs, has the potential to address several challenges associated with the soybean- or egg yolk-based supply chain. However, poor enzyme properties and inefficient microbial expression systems for PLD limit their wide industrial dissemination. Therefore, sourcing new enzyme variants with improved properties and developing advanced PLD expression systems are important. In the present review, we systematically summarize recent achievements and trends in the discovery, their structural properties, catalytic mechanisms, expression strategies for enhancing PLD production, and its multiple applications in the context of PLs. This review is expected to assist researchers to understand current advances in this field and provide insights for further molecular engineering efforts toward PLD-mediated bioprocessing.


Assuntos
Fosfolipase D , Biocatálise , Catálise , Fosfolipase D/genética , Fosfolipase D/metabolismo , Fosfolipídeos , Glycine max
10.
Bioprocess Biosyst Eng ; 43(12): 2201-2207, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32661565

RESUMO

To improve nicotinic acid (NA) yield and meet industrial application requirements of sodium alginate-polyvinyl alcohol (SA-PVA) immobilized cells of Pseudomonas putida mut-D3 harboring nitrilase, inorganic materials were added to the SA-PVA immobilized cells to improve mechanical strength and mass transfer performance. The concentrations of inorganic materials were optimized to be 2.0% silica and 0.6% CaCO3. The optimal pH and temperature for SA-PVA immobilized cells and composite immobilized cells were both 8.0 and 45 °C, respectively. The half-lives of composite immobilized cells were 271.48, 150.92, 92.92 and 33.12 h, which were 1.40-, 1.35-, 1.22- and 1.63-fold compared to SA-PVA immobilized cells, respectively. The storage stability of the composite immobilized cells was slightly increased. The composite immobilized cells could convert 14 batches of 3-cyanopyridine with feeding concentration of 250 mM and accumulate 418 g ·L-1 nicotinic acid, while the SA-PVA immobilized cells accumulated 346 g L-1 nicotinic acid.


Assuntos
Alginatos/química , Aminoidrolases/química , Álcool de Polivinil/química , Pseudomonas putida/enzimologia , Biocatálise , Carbonato de Cálcio , Células Imobilizadas , Ácidos Hexurônicos , Hidroliases , Concentração de Íons de Hidrogênio , Compostos Inorgânicos , Microscopia Eletrônica de Transmissão , Niacina/química , Piridinas/química , Dióxido de Silício/química , Temperatura
11.
Bioprocess Biosyst Eng ; 42(7): 1185-1194, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30989410

RESUMO

Phosphatidylserine is widely used in food, health, chemical and pharmaceutical industries. The phospholipase D-mediated green synthesis of phosphatidylserine has attracted substantial attention in recent years. In this study, the phospholipase D was heterologously expressed in Bacillus subtilis, Pichia pastoris, and Corynebacterium glutamicum, respectively. The highest activity of phospholipase D was observed in C. glutamicum, which was 0.25 U/mL higher than these in B. subtilis (0.14 U/mL) and P. pastoris (0.22 U/mL). System engineering of three potential factors, including (1) signal peptides, (2) ribosome binding site, and (3) promoters, was attempted to improve the expression level of phospholipase D in C. glutamicum. The maximum phospholipase D activity reached 1.9 U/mL, which was 7.6-fold higher than that of the initial level. The enzyme displayed favorable transphosphatidylation activity and it could efficiently catalyze the substrates L-serine and soybean lecithin for synthesis of phosphatidylserine after optimizing the conversion reactions in detail. Under the optimum conditions (trichloromethane/enzyme solution 4:2, 8 mg/mL soybean lecithin, 40 mg/mL L-serine, and 15 mM CaCl2, with shaking under 40 °C for 10 h), the reaction process showed 48.6% of conversion rate and 1.94 g/L of accumulated phosphatidylserine concentration. The results highlight the use of heterologous expression, system engineering, and process optimization strategies to adapt a promising phospholipase D for efficient phosphatidylserine production in synthetic application.


Assuntos
Biocatálise , Fosfatidilserinas/química , Fosfolipase D , Engenharia de Proteínas , Bacillus subtilis/enzimologia , Bacillus subtilis/genética , Corynebacterium glutamicum/enzimologia , Corynebacterium glutamicum/genética , Fosfolipase D/química , Fosfolipase D/genética , Pichia/enzimologia , Pichia/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Especificidade por Substrato
12.
Proteomics ; 17(17-18)2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28792668

RESUMO

Medicinal mushroom Antrodia camphorata sporulate large numbers of arthroconidia in submerged fermentation, which is rarely reported in basidiomycetous fungi. Nevertheless, the molecular mechanisms underlying this asexual sporulation (conidiation) remain unclear. Here, we used comparative transcriptomic and proteomic approaches to elucidate possible signaling pathway relating to the asexual sporulation of A. camphorata. First, 104 differentially expressed proteins and 2586 differential cDNA sequences during the culture process of A. camphorata were identified by 2DE and RNA-seq, respectively. By applying bioinformatics analysis, a total of 67 genes which might play roles in the sporulation were obtained, and 18 of these genes, including fluG, sfgA, SfaD, flbA, flbB, flbC, flbD, nsdD, brlA, abaA, wetA, ganB, fadA, PkaA, veA, velB, vosA, and stuA might be involved in a potential FluG-mediated signaling pathway. Furthermore, the mRNA expression levels of the 18 genes in the proposed FluG-mediated signaling pathway were analyzed by quantitative real-time PCR. In summary, our study helps elucidate the molecular mechanisms underlying the asexual sporulation of A. camphorata, and provides also useful transcripts and proteome for further bioinformatics study of this valuable medicinal mushroom.


Assuntos
Antrodia/crescimento & desenvolvimento , Antrodia/metabolismo , Proteínas Fúngicas/metabolismo , Proteoma/metabolismo , Transdução de Sinais , Esporos Fúngicos/metabolismo , Antrodia/genética , Regulação Fúngica da Expressão Gênica , Proteômica/métodos , Reprodução Assexuada , Transcriptoma
13.
Crit Rev Biotechnol ; 37(1): 69-81, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26700071

RESUMO

Nitrile-converting enzymes, including nitrilase and nitrile hydratase (NHase), have received increasing attention from researchers of industrial biocatalysis because of their critical role as a tool in organic synthesis of carboxylic acids and amides from nitriles. To date, these bioconversion approaches are considered as one of the most potential industrial processes using resting cells or purified enzymes as catalysts for production of food additives, pharmaceutical, and agrochemical precursors. This review focuses on the distribution and catalytic mechanism research of nitrile-converting enzymes in recent years. Molecular biology aspects to improve the biocatalytic performance of microbial nitrilase and NHase are demonstrated. The process developments of microbial nitrilase and NHase for organic synthesis are also discussed.


Assuntos
Aminoidrolases/metabolismo , Hidroliases/metabolismo , Nitrilas/metabolismo , Biocatálise , Técnicas de Química Sintética
14.
Biotechnol Appl Biochem ; 64(4): 519-524, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27189415

RESUMO

An alginate lyase producing bacterial strain, Cobetia sp. WG-007, was isolated and identified from rotting seaweed. The alginate lyase, Aly-W02, was purified by procedures of ultrafiltration, Q-Sepharose Fast Flow, Phenyl Sepharose 6 Fast Flow, and Superdex-G100 with specific activity of 21,285.5 U/mg. Aly-W02 had an apparent molecular mass of 35 kDa. It exhibited maximum activity at 45 °C in 50 mM sodium phosphate buffer (pH 8.5). This alginate lyase was stable in the pH range of 6.0-8.5. Among the tested metal ions, the addition of K+ , Na+ , and Mg2+ ions can enhance the enzyme activities, while Ba2+ , Ni+ , Cu2+ , Mn2+ , Zn2+ , Ag+ , and ethylenediaminetetraacetic acid decreased the activities. It displayed high salt-tolerant ability; 0.8 M NaCl or 1.5 M KCl significantly enhanced the enzyme activity. Furthermore, Aly-W02 mainly released disaccharide, trisaccharide, and tetrasaccharid from alginate. It showed potential in producing low molecular weight alginate oligosaccharides.


Assuntos
Halomonadaceae/enzimologia , Polissacarídeo-Liases/isolamento & purificação , Polissacarídeo-Liases/metabolismo , Tolerância ao Sal , Concentração de Íons de Hidrogênio , Fosfatos/farmacologia , Polissacarídeo-Liases/química , Cloreto de Potássio/farmacologia , Cloreto de Sódio/farmacologia
15.
Bioprocess Biosyst Eng ; 40(6): 901-910, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28285455

RESUMO

3-Hydroxypropionic acid (3-HP) is an important platform chemical in organic synthesis. Traditionally, 3-HP was produced by chemical methods and fermentation process. In this work, a novel enzymatic method was developed for green synthesis of 3-HP. A yeast strain harboring nitrile-hydrolyzing enzyme was newly isolated from environmental samples using 3-hydroxypropionitrile (3-HPN) as the sole nitrogen source. It was identified to be Meyerozyma guilliermondii CGMCC12935 by sequencing of the 18S ribosomal DNA and internal transcribed spacer, together with analysis of the morphology characteristics. The catalytic properties of M. guilliermondii CGMCC12935 resting cells were determined, and the optimum activity was achieved at 55 °C and pH 7.5. The enzyme showed broad substrate specificity towards nitriles, especially 3-HPN, aminoacetonitrile and 3-cyanopyridine. The presence of Ag+, Pb2+ and excess substrate inhibited the enzyme activity, whereas 5% (v/v) ethyl acetate had a positive effect on the enzyme activity. M. guilliermondii CGMCC12935 resting cells by addition of 3% glucose could thoroughly hydrolyze 500 mM 3-HPN into 3-HP within 100 h and the maximal accumulative production of 3-HP reached 216.33 mM, which was over twofolds than the control group with no additional glucose. And this work would lay the foundation for biological production of 3-HP in industry.


Assuntos
Candida , Ácido Láctico/análogos & derivados , Nitrilas , Piridinas
16.
Appl Environ Microbiol ; 82(19): 5860-8, 2016 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-27451452

RESUMO

UNLABELLED: Acetoin (3-hydroxy-2-butanone) formation in vinegar microbiota is crucial for the flavor quality of Zhenjiang aromatic vinegar, a traditional vinegar produced from cereals. However, the specific microorganisms responsible for acetoin formation in this centuries-long repeated batch fermentation have not yet been clearly identified. Here, the microbial distribution discrepancy in the diacetyl/acetoin metabolic pathway of vinegar microbiota was revealed at the species level by a combination of metagenomic sequencing and clone library analysis. The results showed that Acetobacter pasteurianus and 4 Lactobacillus species (Lactobacillus buchneri, Lactobacillus reuteri, Lactobacillus fermentum, and Lactobacillus brevis) might be functional producers of acetoin from 2-acetolactate in vinegar microbiota. Furthermore, A. pasteurianus G3-2, L. brevis 4-22, L. fermentum M10-3, and L. buchneri F2-5 were isolated from vinegar microbiota by a culture-dependent method. The acetoin concentrations in two cocultures (L. brevis 4-22 plus A. pasteurianus G3-2 and L. fermentum M10-3 plus A. pasteurianus G3-2) were obviously higher than those in monocultures of lactic acid bacteria (LAB), while L. buchneri F2-5 did not produce more acetoin when coinoculated with A. pasteurianus G3-2. Last, the acetoin-producing function of vinegar microbiota was regulated in situ via augmentation with functional species in vinegar Pei After 72 h of fermentation, augmentation with A. pasteurianus G3-2 plus L. brevis 4-22, L. fermentum M10-3, or L. buchneri F2-5 significantly increased the acetoin content in vinegar Pei compared with the control group. This study provides a perspective on elucidating and manipulating different metabolic roles of microbes during flavor formation in vinegar microbiota. IMPORTANCE: Acetoin (3-hydroxy-2-butanone) formation in vinegar microbiota is crucial for the flavor quality of Zhenjiang aromatic vinegar, a traditional vinegar produced from cereals. Thus, it is of interest to understand which microbes are driving the formation of acetoin to elucidate the microbial distribution discrepancy in the acetoin metabolic pathway and to regulate the metabolic function of functional microbial groups in vinegar microbiota. Our study provides a perspective on elucidating and manipulating different metabolic roles of microbes during flavor formation in vinegar microbiota.


Assuntos
Ácido Acético/metabolismo , Acetobacter/metabolismo , Acetoína/metabolismo , Lactobacillus/metabolismo , Acetobacter/genética , Diacetil/metabolismo , Fermentação , Marcação de Genes , Lactobacillus/genética , Redes e Vias Metabólicas , Metagenômica , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Especificidade da Espécie
17.
Bioprocess Biosyst Eng ; 39(1): 193-204, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26589609

RESUMO

Microbial keratinase is a well-recognized enzyme that can specifically degrade insoluble keratins. A keratinase-producing bacterium was isolated from a duck ranch soil and identified as Acinetobacter sp. R-1 based on the biochemical characteristics and 16S rDNA gene sequencing. It showed high keratinase activity and low collagenase activity. The keratinase was purified to electrophoretic homogeneity with 6.69% recovery, 2.68-fold purification and an estimated molecular weight of 25 kDa. Additionally, the keratinase showed optimal activity at 50 °C and pH11. Keratinase activity of Acinetobacter sp. significantly increased in the presence of Li(+), Na(+), and Ca(2+), while it was completely inhibited by EDTA, indicating it was a metallo-keratinase. Moreover, the crude keratinase from Acinetobacter sp. R-1 could thoroughly depilate goat skin and simultaneously modify the wool surface, which indicated its applicable potential in leather and textile industries.


Assuntos
Acinetobacter , Proteínas de Bactérias/química , Colagenases/química , Metaloproteases/química , Peptídeo Hidrolases/química , Acinetobacter/enzimologia , Acinetobacter/genética , Acinetobacter/isolamento & purificação , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Colagenases/genética , Colagenases/metabolismo , Cabras , Metaloproteases/genética , Metaloproteases/metabolismo , Peptídeo Hidrolases/genética , Peptídeo Hidrolases/metabolismo , Pele , Indústria Têxtil ,
18.
Bioprocess Biosyst Eng ; 38(1): 189-97, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25030338

RESUMO

Comparative studies of immobilized and free cells of Gibberella intermedia CA3-1 in bioconversion of 3-cyanopyridine to nicotinic acid were performed. Entrapping method was chosen based on the advantages in enzymatic activity recovery, mechanical strength and preparation procedure. Four entrapment matrices were investigated and sodium alginate was screened to be the most suitable material. Maximal nitrilase activity of alginate immobilized cells was obtained under conditions of 2 % alginate, 0.6 % CaCl2, 0.4 g cell/g alginate, 1.8 mm bead size. The immobilized cells showed excellent substrate tolerance even when the 3-cyanopyridine concentration was 700 mM. The half-lives of immobilized cells at 30, 40 and 50 °C were 315, 117.5 and 10.9 h, respectively, correspondingly 1.4, 1.6 and 1.7-fold compared with that of the free cells. Efficient reusability of immobilized cells up to 28 batches was achieved and 205.7 g/(g dcw) nicotinic acid was obtained with 80.55 % enzyme activity preserved.


Assuntos
Aminoidrolases/metabolismo , Gibberella/enzimologia , Reatores Biológicos , Catálise , Células Imobilizadas , Estabilidade Enzimática , Meia-Vida , Concentração de Íons de Hidrogênio , Microscopia Eletrônica de Varredura , Piridinas/metabolismo , Especificidade por Substrato , Temperatura
19.
Int J Mol Sci ; 16(12): 30061-74, 2015 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-26694369

RESUMO

In the present study, we isolated a trypsin-producing strain DMN6 from the leather waste and identified it as Bacillus licheniformis through a two-step screening strategy. The trypsin activity was increased up to 140 from 20 U/mL through culture optimization. The enzyme was purified to electrophoretic homogeneity with a molecular mass of 44 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the specific activity of purified enzyme is 350 U/mg with Nα-Benzoyl-L-arginine ethylester as the substrate. The optimum temperature and pH for the trypsin are 65 °C and pH 9.0, respectively. Also, the enzyme can be significantly activated by Ba(2+). This enzyme is relatively stable in alkaline environment and displays excellent activity at low temperatures. It could retain over 95% of enzyme activity after 180 min of incubation at 45 °C. The distinguished activity under low temperature and prominent stability enhance its catalytic potential. In the current work, the open reading frame was obtained with a length of 1371 nucleotides that encoded a protein of 456 amino acids. These data would warrant the B. licheniformis trypsin as a promising candidate for catalytic application in collagen preparation and leather bating through further protein engineering.


Assuntos
Álcalis/metabolismo , Arginina/metabolismo , Bacillus/enzimologia , Tripsina/metabolismo , Sequência de Aminoácidos , Bacillus/genética , Bacillus/isolamento & purificação , Sequência de Bases , Clonagem Molecular , Eletroforese em Gel de Poliacrilamida , Estabilidade Enzimática/efeitos dos fármacos , Fermentação/efeitos dos fármacos , Genes Bacterianos , Concentração de Íons de Hidrogênio , Íons , Cinética , Metais/farmacologia , Dados de Sequência Molecular , Filogenia , RNA Ribossômico 16S/genética , Alinhamento de Sequência , Especificidade por Substrato/efeitos dos fármacos , Temperatura , Tripsina/química , Inibidores da Tripsina/farmacologia
20.
Int J Biol Macromol ; 262(Pt 1): 129928, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38309393

RESUMO

Trehalase has attracted widespread attention in medicine, agriculture, food, and ethanol industry due to its ability to specifically degrade trehalose. Efficient expression of trehalase remains a challenge. In this study, a putative trehalase-encoding gene (Tre-zm) from Zunongwangia mangrovi was explored using gene-mining strategy and heterologously expressed in E. coli. Trehalase activity reached 3374 U·mL-1 after fermentation optimization. The scale-up fermentation in a 15 L fermenter was achieved with a trehalase production of 15,068 U·mL-1. The recombinant trehalase TreZM was purified and characterized. It displayed optimal activity at 35 °C and pH 8.5, with Mn2+, Sn2+, Na+, and Fe2+ promoting the activity. Notably, TreZM showed significant inhibition effect on biofilm forming of Staphylococcus epidermidis. The combination of TreZM with a low concentration of antibiotics could inhibit 70 % biofilm formation of Staphylococcus epidermidis and 28 % of Pseudomonas aeruginosa. Hence, this study provides a promising candidate for industrial production of trehalase and highlights its potential application to control harmful biofilms.


Assuntos
Escherichia coli , Trealase , Trealase/química , Escherichia coli/genética , Escherichia coli/metabolismo , Fermentação , Trealose/farmacologia , Trealose/metabolismo , Biofilmes
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