Journal of Industrial Microbiology & Biotechnology最新文献

The equine gut harbours a diverse microbial community and represents a rich source of carbohydrate-active enzymes (CAZymes). To identify and characterize potentially novel CAZymes from a horse's hindgut metagenome, shotgun metagenomic sequencing was performed on DNA extracted from a stool sample of a male horse followed by CAZyme annotation. Here, we report on the characterization of a novel enzyme (AH2) that was identified, synthesized, cloned and characterized from the obtained CAZyme dataset. AH2 was identified as a GH130 family member and displayed an exclusive xylanase activity, a trait hitherto unreported in prior characterization of GH130 CAZymes. AH2 displayed an optimal activity at a pH of 5.6 and a temperature of 50°C. AH2 maintained significant activity across a pH range of 4 to 10 (62 -72%) and temperatures of 30 to 70°C (77-86%). The enzyme had remarkable stability, with minimal reductions in activity across a temperature range of 4 to 70°C and pH levels of 3, 7, and 9. Docking studies identified AH2's amino acids (Glu90 and Glu149) to be involved in substrate binding. Molecular dynamics simulation confirmed the structural stability of AH2 at pH 5.6 and 50°C, further supporting its resilience under these conditions. Our results expand on the known activities associated with the GH130 CAZyme family and demonstrate that the horse gut metagenome represents an unexplored source of novel CAZymes.

Nucleoside deoxyribosyl transferase (NDT) is an enzyme that catalyzes the transfer of purine and pyrimidine bases between 2'-deoxyribonucleosides and is widely used for synthesizing nucleoside analogs in various biotechnological applications. While NDT exhibits high activity toward natural nucleosides, its activity toward unnatural nucleoside analogs is significantly lower. Previously, the NDT mutant named fNDT(L59Q) was identified displaying 4.4-fold higher activity toward 2'-fluoro-2'-deoxyuridine (2FDU). In this study, molecular evolution strategies using error-prone PCR were employed to further generate mutant enzymes with enhanced activity toward 2FDU. After two rounds of mutational screening, two mutant clones that exhibited high activity against 2FDU were identified as fNDT-i1 (V52A) and fNDT-i2 (L28I), respectively. A double mutant fNDT-i4, was subsequently constructed by combining the V52A and L28I mutations. Whole-cell-based activity measurements showed that fNDT-i4 exhibited 4.0-fold and 20.6-fold higher activity at 40°C and 50°C, respectively, compared to the wild-type NDT. The detailed characterization of the purified enzymes conducted under various conditions, including temperature, pH, thermal stability, and enzyme kinetics experiments, showed that fNDT-i1 and fNDT-i4 exhibited 3.1- and 3.7-fold higher catalytic efficiency, respectively than wild-type NDT. The L59Q mutation was identified as a key factor in improving the thermal stability, whereas the V52A and L28I mutations were critical for improving substrate affinity and reaction efficiency. These findings provide the potential of fNDT-i1 and fNDT-i4 as highly efficient biocatalysts for developing industrially relevant nucleoside analog synthesis.

Biocatalysis provides access to synthetically challenging molecules and commercially and pharmaceutically relevant natural product analogs while adhering to principles of green chemistry. Cytochromes P450 (P450s) are among the most superlative and versatile oxidative enzymes found in nature and are desired regio- and stereoselective biocatalysts, particularly for structurally complex hydrocarbon skeletons. We used 10 genome-sequenced Streptomyces strains, selected based on their preponderance of P450s, to biotransform the bioactive diterpenoid abietic acid. We isolated and structurally characterized seven oxidized abietic acid derivatives from three different strains, including four products that are new bacterial biotransformants or enzymatic products. Oxidations (hydroxylation, dehydrogenation, and aromatization) were seen on both the B and C rings of abietic acid and five products had multiple modifications. Notable conversions observed in the study were that of abietic acid to 15-hydroxy-7-oxo-8,11,13-abietatrien-18-oic acid, 7, which involves multiple hydroxylation reactions and dehydrogenation. The findings from this study will lead to identifying P450s or other enzymes that may act as general biocatalysts to modify abietanes and other labdane-type diterpenoid skeletons.

One-sentence summary: Genome-guided biotransformation of the bioactive diterpenoid abietic acid in Streptomyces yielded seven oxidized derivatives including four that have not been previously seen from bacteria.

In a world where concrete structures face constant degradation from environmental forces, a revolutionary solution has emerged: bio-self-healing concrete. This innovation involves embedding dormant bacteria within the concrete mix, poised to spring into action when cracks form. As moisture seeps into the cracks, these bacterial agents are activated, consuming nutrients and converting them into calcium carbonate, a natural substance that fills and repairs the fractures, restoring the material's integrity. This fascinating process represents a cutting-edge approach to maintaining concrete infrastructure, turning once-vulnerable materials into self-sustaining systems capable of healing themselves. The ongoing research into bio-self-healing concrete is focused on selecting bacterial strains that can withstand the extreme conditions within concrete, including its highly alkaline environment. The bacteria must also form resilient spores, remaining viable until they are needed for repair. Additionally, the study explores various challenges associated with this technology, such as the cost of production, the bacteria's long-term viability, and their potential environmental impact. Advancements in genetic engineering and smart technology are being explored to enhance these bacterial strains, making them more efficient and robust in their role as microscopic repair agents. This review delves into the potential of bio-self-healing concrete to revolutionize how we approach infrastructure maintenance, offering a glimpse into a future where concrete structures not only endure but actively repair themselves, extending their lifespan and reducing the need for costly repairs.

One-sentence summary: Bio-self-healing concrete utilizes bacteria that activate upon crack formation to repair structures by producing calcium carbonate, offering a sustainable solution to prolong the lifespan of concrete infrastructure.

Ulvan is a complex sulfated polysaccharide in the cell walls of green algae with extensive applications in food, pharmaceutical, and agricultural industries, prompting extensive studies on ulvan, its oligosaccharides, monosaccharides, and cost-effective depolymerization methods. Our primary objectives were to investigate novel ulvan-utilizing marine bacteria, perform recombinant engineering of genes responsible for ulvan depolymerization, and determine their potential industrial applications. Samples were collected from Jeju Island, which is a South Korean region with significant excessive green algal growth, especially that of Ulva species. The marine bacterium Pseudoalteromonas agarivorans efficiently uses ulvan as its primary carbon source, indicating its potential for ulvan degradation. Through whole-genome sequencing the paul40 gene, which is a polysaccharide lyase family 40 (PL40) member, was identified and subsequently engineered into the pET-16b vector for expression as a His-tagged 95 kDa fusion protein. The ulvan depolymerization process was evaluated and confirmed using various analytical techniques including dinitrosalicylic acid assay, thin-layer chromatography, and gel permeation chromatography. Optimal enzyme activity occurred at 35°C, pH 8.0 in phosphate buffer, and 2.5 mM of NaCl. Furthermore, enzyme characterization and specific activity measurements were performed. This study is the first to report hyaluronidase and elastase inhibition by ulvan and its derivatives along with the characterization of an ulvan lyase enzyme from the PL40 family.

One-sentence summary: This study reports the identification and recombinant expression of a novel ulvan-degrading enzyme from Pseudoalteromonas agarivorans, demonstrating its potential for cosmetic industrial applications by revealing ulvan's and partially hydrolyzed ulvan's hyaluronidase and elastase inhibition properties.

In this review, we focus on how purple non-sulfur bacteria can be leveraged for sustainable bioproduction to support the circular economy. We discuss the state of the field with respect to the use of purple bacteria for energy production, their role in wastewater treatment, as a fertilizer, and as a chassis for bioplastic production. We explore their ability to serve as single-cell protein and production platforms for fine chemicals from waste materials. We also introduce more Avant-Garde technologies that leverage the unique metabolisms of purple bacteria, including microbial electrosynthesis and co-culture. These technologies will be pivotal in our efforts to mitigate climate change and circularize the economy in the next two decades.

One-sentence summary: Purple non-sulfur bacteria are utilized for a range of biotechnological applications, including the production of bio-energy, single cell protein, fertilizer, bioplastics, fine chemicals, in wastewater treatment and in novel applications like co-cultures and microbial electrosynthesis.

Microbial isolates from sugar crop processing facilities were tested for sensitivity to several industrial antimicrobial agents to determine optimal dosing. Hydritreat 2216 showed broad-spectrum activity against all bacterial isolates as well as Saccharomyces cerevisiae. Sodium hypochlorite showed broad-spectrum activity against all isolates, but at much higher effective concentrations. Hops BetaStab XL was effective against Gram-positive isolates. Magna Cide D minimum inhibitory concentration was lowest for S. cerevisiae and Zymomonas mobilis but was less effective against Gram-positive bacterial strains. Based on laboratory experiments, factory losses of sucrose from a single microbial species in the absence of antimicrobials could range from 0.13 to 0.52 kg of sucrose per tonne of cane. Additional improvements in sugar yield are anticipated from agents with broad-spectrum activity. A cost analysis was conducted considering sucrose savings due to antimicrobial application to provide estimates for break-even costs, which ranged from approximately $0.50 to $2.00/L for a given antimicrobial agent.

One-sentence summary: Application of antimicrobial agents at minimal inhibitory doses for microbes results in optimal inhibition of microbial growth and sucrose consumption.