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1.
Yi-Huang Hsueh Ping-Han Tsai Kuen-Song Lin Wan-Ju Ke Chao-Lung Chiang 《Journal of nanobiotechnology》2017,15(1):77
Background
Zero-valent iron nanoparticles (ZVI NPs) have been used extensively for the remediation of contaminated soil and groundwater. Owing to their large active surface area, they serve as strong and effective reductants. However, the ecotoxicity and bioavailability of ZVI NPs in diverse ecological media have not been evaluated in detail and most studies have focused on non-nano ZVI or Fe0. In addition, the antimicrobial properties of ZVI NPs have rarely been investigated, and the underlying mechanism of their toxicity remains unknown.Results
In the present study, we demonstrate that ZVI NPs exhibited significant toxicity at 1000 ppm against two distinct gram-positive bacterial strains (Bacillus subtilis 3610 and Bacillus thuringiensis 407) but not against two gram-negative strains (Escherichia coli K12 and ATCC11634). Specifically, ZVI NPs caused at least a 4-log and 1-log reductions in cell numbers, respectively, in the two Bacillus strains, whereas no change was detected in the two E. coli strains. X-ray photoelectron spectroscopy, X-ray absorption near-edge, and extended X-ray absorption fine structure spectra confirmed that Bacillus cells exposed to ZVI NPs contained mostly Fe2O3 with some detectable FeS. This finding indicated that Fe0 nanoparticles penetrated the bacterial cells, where they were subsequently oxidized to Fe2O3 and FeS. RedoxSensor analysis and propidium iodide (PI) staining showed decreased reductase activity and increased PI in both Bacillus strains treated with a high (1000 ppm) concentration of ZVI NPs.Conclusion
Taken together, these data show that the toxicity of ZVI NPs was derived from their oxidative properties, which may increase the levels of reactive oxygen species and lead to cell death.2.
Songwen Tan Xuncai Chen Chunzhi Cui Yang Hou Weiguo Li Hong You 《Biotechnology letters》2017,39(1):91-96
Objective
To develop a method to treat saline phenolic wastewater in a biological contact oxidation reactor (BCOR) with immobilized cells of a marine microorganism, Oceanimonas sp., isolated from seawater.Results
Cells were immobilized on fibre carriers in the BCOR. Saline wastewater with phenol at 1.5 g/l and NaCl at 6 % (w/v) was treated. In continuous assays, 99 % removal of phenol was achieved and a kinetic model for the phenol degradation is presented based on Monod’s equation.Conclusion
The BOCR system using immobilized cells of Oceanimonas efficiently treats saline phenolic wastewaters without having decrease the salinity of the wastewater.3.
Objectives
To demonstrate biotransformation of toxic Cr(VI) ions into Cr2O3 nanoparticles by the yeast Schwanniomyces occidentalis.Results
Reaction mixtures containing S. occidentalis NCIM 3459 and Cr(VI) ions that were initially yellow turned green after 48 h incubation. The coloration was due to the synthesis of chromium (III) oxide nanoparticles (Cr2O3NPs). UV–Visible spectra of the reaction mixtures showed peaks at 445 and 600 nm indicating 4A2g → 4T1g and 4A2g → 4T2g transitions in Cr2O3, respectively. FTIR profiles suggested the involvement of carboxyl and amide groups in nanoparticle synthesis and stabilization. The Cr2O3NPs ranged between 10 and 60 nm. Their crystalline nature was evident from the selective area electron diffraction and X-ray diffraction patterns. Energy dispersive spectra confirmed the chemical composition of the nanoparticles. These biogenic nanoparticles could find applications in different fields.Conclusions
S. occidentalis mediated biotransformation of toxic Cr(VI) ions into crystalline extracellular Cr2O3NPs under benign conditions.4.
Seyed Ziyae Aldin Samsam Shariat Fatemeh Borzouee Mohammad Reza Mofid Jaleh Varshosaz 《Biotechnology letters》2018,40(9-10):1343-1353
Objectives
The purpose of this study was to develop a facile and efficient method to enhance the stability and activity of lactoperoxidase (LPO) by using its immobilization on graphene oxide nanosheets (GO-NS).Methods
Following the LPO purification from bovine whey, it was immobilized onto functionalized GO-NS using glutaraldehyde as cross-linker. Kinetic properties and stability of free and immobilized LPO were investigated.Results
LPO was purified 59.13 fold with a specific activity of 5.78 U/mg protein. The successful immobilization of LPO on functionalized GO-NS was confirmed by using dynamic light scattering (DLS) and Fourier transform infrared spectroscopy (FT-IR). The overall results showed that the stability of the immobilized LPO was considerably improved compared to free LPO. Apparent Km and Vmax of LPO also indicated that the immobilized enzyme had greater affinity to the substrate than the native enzyme.Conclusions
Graphene oxide nanosheets are effective means for immobilization of LPO.5.
Objective
To explore the glycerol utilization pathway in Corynebacterium glutamicum for succinate production under O2 deprivation.Result
Overexpression of a glycerol facilitator, glycerol dehydrogenase and dihydroxyacetone kinase from Escherichia coli K-12 in C. glutamicum led to recombinant strains NC-3G diverting glycerol utilization towards succinate production under O2 deprivation. Under these conditions, strain NC-3G efficiently consumed glycerol and produced succinate without growth. The recombinant C. glutamicum utilizing glycerol as the sole carbon source showed higher intracellular NADH/NAD+ ratio compare with utilizing glucose. The mass conversion of succinate increased from 0.64 to 0.95. Using an anaerobic fed-batch fermentation process, the final strain produced 38.4 g succinate/l with an average yield of 1.02 g/g.Conclusions
The metabolically-engineered strains showed an efficient succinate production using glycerol as sole carbon source under O2 deprivation.6.
Background
Au/CuS core/shell nanoparticles (NPs) were designed as a new type of transducer agent for photothermal therapy (PTT), with attractive features of easy preparation, low cost and small size for targeting. This paper studied for the first time the intrinsic antimicrobial activity of Au/CuS NPs to B. anthracis spores and cells in addition to its PTT effect.Results
It was found that Au/CuS NPs were highly efficient in inactivating B. anthracis cells, but not effective to the spores. Treatment with NPs at ~0.83 μM for 30 min achieved a 7 log reduction in viable cells. The antimicrobial effect was both NPs concentration and treatment time dependent. SEM imaging and the efflux of DNA test demonstrated the damage of cell membrane after NPs treatment, yet further research is necessary to fully understand the precise inactivation mechanism.Conclusions
The Au/CuS NPs had strong antimicrobial activity to B. anthracis cells, which showed a great potential to be an effective antimicrobial agent to bacterial cells.7.
Joon-Geun Ha Young Seok Song Sunghwan Jung Soohwan Jang Yong-Kweon Kim Seoung Jai Bai Jae-Hyoung Park Seung-Ki Lee 《Biotechnology letters》2017,39(6):849-855
Objective
To fabricate a novel microbial photobioelectrochemical cell using silicon microfabrication techniques.Results
High-density photosynthetic cells were immobilized in a microfluidic chamber, and ultra-microelectrodes in a microtip array were inserted into the cytosolic space of the cells to directly harvest photosynthetic electrons. In this way, the microbial photobioelectrochemical cell operated without the aid of electron mediators. Both short circuit current and open circuit voltage of the microbial photobioelectrochemical cell responded to light stimuli, and recorded as high as 250 pA and 45 mV, respectively.Conclusion
A microbial photobioelectrochemical cell was fabricated with potential use in next-generation photosynthesis-based solar cells and sensors.8.
Jizhong Wang Chengli Yang Xing Chen Bingxin Bao Xuan Zhang Dali Li Xingfan Du Ruofu Shi Junfang Yang Ronghui Zhu 《Biotechnology letters》2016,38(8):1315-1320
Objectives
To find an efficient and cheap system for NAD+ regenerationResults
A NADH-ferricyanide dehydrogenase was obtained from an isolate of Escherichia coli. Optimal activity of the NADH dehydrogenase was at 45 °C and pH 7.5, with a K m value for NADH of 10 μM. By combining the NADH dehydrogenase, potassium ferricyanide and laccase, a bi-enzyme system for NAD+ regeneration was established. The system is attractive in that the O2 consumed by laccase is from air and the sole byproduct of the reaction is water. During the reaction process, 10 mM NAD+ was transformed from NADH in less than 2 h under the condition of 0.5 U NADH dehydrogenase, 0.5 U laccase, 0.1 mM potassium ferricyanide at pH 5.6, 30 °CConclusion
The bi-enzyme system employed the NADH-ferricyanide dehydrogenase and laccase as catalysts, and potassium ferricyanide as redox mediator, is a promising alternative for NAD+ regeneration.9.
Chenchen Zhang Jingyu Lu Duo Yang Xia Chen Yujun Huang Ruixia Gu 《Biotechnology letters》2018,40(4):729-735
Objective
To investigate the aerotolerance of Lactobacillus rhamnosus hsryfm 1301 and its influencing factors.Results
The growth rate of L. rhamnosus hsryfm 1301 weakened noticeably when the concentration of supplemented H2O2 reached 1 mM, and only 2% of all L. rhamnosus hsryfm 1301 cells survived in MRS broth supplemented with 2 mM H2O2 for 1 h. After pretreatment with 0.5 mM H2O2, the surviving cells of L. rhamnosus hsryfm 1301 in the presence of 5 mM H2O2 for 1 h increased from 3.7 to 7.8 log CFU. Acid stress, osmotic stress, and heat stress at 46 °C also enhanced its aerotolerance, while heat stress at 50 °C reduced the tolerance of L. rhamnosus hsryfm 1301 to oxidative stress. Moreover, treatment with 0.5 mM H2O2 increased the heat stress tolerance of L. rhamnosus hsryfm 1301 by approximately 150-fold.Conclusions
Lactobacillus rhamnosus hsryfm 1301 possesses a stress-inducible defense system against oxidative stress, and the cross-adaptation to different stresses is a promising target to increase the stress tolerance of L. rhamnosus hsryfm 1301 during probiotic food and starter culture production.10.
Xiaobo Dong Haiyun Li Yucheng Jiang Mancheng Hu Shuni Li Quanguo Zhai 《Biotechnology letters》2016,38(9):1483-1491
Objectives
To degrade enzymatically bisphenol A (BPA) that causes serious environmental concerns and is difficult to be degraded by chemical or physical methods.Results
BPA (150 mg l?1) was completely degraded by chloroperoxidase (CPO)/H2O2 within 7 min at room temperature, atmospheric pressure with the enzyme at 6 μg CPO ml?1. The degradation products were identified by HPLC–MS, which suggested involvement of multiple steps. Enzymatic treatment followed by existing bioremediation technologies (activated sludge) enhanced removal of COD from 9 to 54 %. Using an ecotoxicity evaluation with Chlorella pyrenoidosa, the degradation products had a lower toxicity than BPA.Conclusion
BPA can be degraded rapidly and efficiently under mild conditions with chloroperoxidase at 6 μg ml?1. The degradation products had a lower toxicity than BPA.11.
Ziqiang Wang Munan Su Yanliang Li Yunshan Wang Zhiguo Su 《Biotechnology letters》2017,39(12):1859-1863
Objective
To investigate the expression and immobilization of recombinant cis-epoxysuccinate hydrolase (ESH), and its application in the biological production of l-(+)-tartaric acid.Results
E. coli BL21 (DE3)/pET11a-ESH (His) was engineered to express recombinant ESH. The enzyme had an activity of 262 U mg?1. The recombinant ESH was immobilized on agarose Ni-IDA matrix with metal ion affinity interaction to improve its thermostability and pH stability. The immobilization efficiency and activity yield were 94 and 95%, respectively. The specific catalytic efficiency of immobilized ESH was 104 mg U?1 h?1 during the continuous enzymatic production process.Conclusion
ESH with a histidine tag was immobilized and used for the continuous production of l-(+)-tartaric acid.12.
Geng Chen Shou-Ying Li Hamid Tayyab Malik Yu-Guang Ma Hong Xu Lian-Kun Sun 《Biotechnology letters》2016,38(8):1269-1276
Objectives
To investigate the biocompatibility of human gastric carcinoma cells (SGC-7901) with organic two-photon nanoparticles (NPs).Results
Different concentrations of NPs were incubated with SGC-7901 cells for different times. The levels of cell apoptosis, reactive oxygen species (ROS), intracellular calcium, and mitochondrial membrane potential (MMP) were measured by staining the SGC-7901 cells with Annexin V-FITC/PI, 2′,7′-dichlorofluorescin diacetate, Fluo-3 AM, and Rhodamine 123, followed by the flow cytometry assay. NPs at <4 µg/ml, did not have any significant effect on apoptosis, necrosis, generation of ROS, increase of intracellular Ca2+ concentration or decrease of MMP in SGC-7901 cells, but >4 µg/ml had a major effects on all the above mentioned parameters.Conclusion
2,5,2′,5′-Tetra(4-N,N-diphenylamine styryl) biphenyl NPs can be used at an appropriate concentration as a safe drug carrier or imaging marker and may serve as an effective tool for developing a photodynamic cancer therapy.13.
Objectives
In this study, a rapid sedimentation induced by combined coagulants and gradual shear was developed to harvest Chlorella vulgaris.Results
The microalgal harvesting efficiency was observably promoted by the synergistic effect between FeCl3 and PAM, especially in the first 10 min. A higher harvesting efficiency, 95.61%, could be achieved within approximately 3 min due to the large and dense flocs generated by the combined coagulants. In contrast, the efficiencies were only 54.25 and 60.20% with FeCl3 and PAM, independently. When coagulation was performed under gradually reduced shear (from 50 to 30 rpm), smaller clusters or cells filled the pores of the aggregates via interception, which caused the flocs to become larger and more compact.Conclusions
The sedimentation time was shortened to 30 s for microalgal coagulation induced by the simultaneous use of combined coagulants and tapered shear, providing an effective approach to harvesting microalgae.14.
Hiroaki Sakamoto Tomohiro Komatsu Koji Yamasaki Takenori Satomura Shin-ichiro Suye 《Biotechnology letters》2017,39(2):235-240
Objectives
To design and construct a novel bio-anode electrode based on the oxidation of glutamic acid to produce 2-oxoglutarate, generating two electrons from NADH.Results
Efficient enzyme reaction and electron transfer were observed owing to immobilization of the two enzymes using a mixed self-assembled monolayer. The ratio of the immobilized enzymes was an important factor affecting the efficiency of the system; thus, we quantified the amounts of immobilized enzyme using a quartz crystal microbalance to further evaluate the electrochemical reaction. The electrochemical reaction proceeded efficiently when approximately equimolar amounts of the enzyme were on the electrode. The largest oxidation peak current increase (171 nA) was observed under these conditions.Conclusion
Efficient multi-enzyme reaction on the electrode surface has been achieved which is applicable for biofuel cell application.15.
Hyerin Kim Young Joo Yeon Yoo Rae Choi Wooho Song Seung Pil Pack Yoo Seong Choi 《Biotechnology letters》2016,38(9):1535-1542
Objectives
To obtain an acidic and cold-active tyrosinase, which potentially minimizes unwanted self-oxidation of tyrosinase-catalyzed catechols, including 3,4-dihydroxyphenylalanine at elevated pH and high temperature.Results
A putative psychrophilic tyrosinase (named as tyrosinase-CNK) was identified from the genome information of the marine archaeon Candidatus Nitrosopumilus koreensis. This protein contains key tyrosinase domains, such as copper-binding domains and an O2-binding motif, and phylogenetic analysis revealed that it was distinct from other known bacterial tyrosinases. Functional tyrosinase-CNK was produced by applying a co-expression strategy together with chaperone proteins in Escherichia coli with a yield of approx. 30 mg l?1 and a purity >95 %. The purified enzyme showed optimal activity at pH 6 and 20 °C and still had 50 % activity at 0 °C. Surprisingly, the enzyme exhibited an abnormally high monophenolase/diphenolase activity ratio.Conclusions
The acidic and cold-adapted tyrosinase-CNK, as a new type of tyrosinase, could expand potential applications of tyrosinases including the production of catechols through minimizing unwanted self-oxidation and the modification of existing materials at low temperature.16.
Arunachalam Kalaiarasi Renu Sankar Chidambaram Anusha Kandasamy Saravanan Kalyanasundaram Aarthy Selvaraj Karthic Theodore lemuel Mathuram Vilwanathan Ravikumar 《Biotechnology letters》2018,40(2):249-256
Objectives
Copper oxide nanoparticles (CuO NPs) promoting anticancer activity may be due to the regulation of various classes of histone deacetylases (HDACs).Results
Green-synthesized CuO NPs significantly arrested total HDAC level and also suppressed class I, II and IV HDACs mRNA expression in A549 cells. A549 cells treated with CuO NPs downregulated oncogenes and upregulated tumor suppressor protein expression. CuO NPs positively regulated both mitochondrial and death receptor-mediated apoptosis caspase cascade pathway in A549 cells.Conclusion
Green-synthesized CuO NPs inhibited HDAC and therefore shown apoptosis mediated anticancer activity in A549 lung cancer cell line.17.
Objectives
To use permeabilized cells of the fission yeast, Schizosaccharomyces pombe, that expresses human UDP-glucose 6-dehydrogenase (UGDH, EC 1.1.1.22), for the production of UDP-glucuronic acid from UDP-glucose.Results
In cell extracts no activity was detected. Therefore, cells were permeabilized with 0.3 % (v/v) Triton X-100. After washing away all low molecular weight metabolites, the permeabilized cells were directly used as whole cell biocatalyst. Substrates were 5 mM UDP-glucose and 10 mM NAD+. Divalent cations were not added to the reaction medium as they promoted UDP-glucose hydrolysis. With this reaction system 5 mM UDP-glucose were converted into 5 mM UDP-glucuronic acid within 3 h.Conclusions
Recombinant permeabilized cells of S. pombe can be used to synthesize UDP-glucuronic acid with 100 % yield and selectivity.18.
Xiao Shen Danijel Dojcinovic Lucia Baldi David L. Hacker Immanuel F. Luescher Florian M. Wurm 《Biotechnology letters》2018,40(1):85-92
Objectives
To investigate the effects of operational process conditions on expression of MHC class II protein from a stable Drosophila S2 cell line.Results
When the Drosophila S2 cells were grown in vented orbitally shaken TubeSpin bioreactor 600 containers, cell growth was improved three-fold and the yield of recombinant major histocompatibility (MHC) class II protein (HLA-DR12xHis) increased four-fold over the levels observed for the same cells cultivated in roller bottles (RB) without vented caps. Culturing in RB with vented caps while increasing the rotation speed from 6 rpm to 18 rpm also improved cell growth five-fold and protein productivity three-fold which is comparable to the levels observed in the orbitally shaken containers. Protein activity was found to be almost identical between the two vessel systems tested.Conclusions
Optimized cell culture conditions and a more efficient vessel type can enhance gas transfer and mixing and lead to substantial improvement of recombinant product yields from S2 cells.19.
Takuya Sugawara Mariko Chinzei Setsuko Numano Chifumi Kitazaki Munehiko Asayama 《Biotechnology letters》2018,40(5):829-836
Objective
A novel filamentous cyanobacterium, a photosynthesizing microorganism, was isolated from a river, and its unique features of flocculation and pentadecane production were characterized.Results
Microscopic observations and a phylogenetic analysis with 16S rDNA revealed that this strain was a Limnothrix species denoted as the SK1-2-1 strain. Auto cell-flocculation was observed when this strain was exposed to a two-step incubation involving a standing cultivation following a shaking preincubation. Flocculation was enhanced by blue light at a wavelength at 470 nm and irradiation for several hours to 1 day. Moreover, the strain exhibiting exponential cell growth may preferentially accumulate alkanes as pentadecane C15H32 alkane, which may be used as jet fuel, at a range of approximately 1% in the dry cell weight of flocculated cells.Conclusion
This is the first study on biofuel production using flocculated cells in which the specific manner of production may be regulated by cultivation conditions.20.
Huihui Xu Yang Zhang Xin Feng Kunyuan Tie Yuan Cao Wenyu Han 《Biotechnology letters》2017,39(6):897-903