scholarly journals Characterization of a Biofilm Bioreactor Designed for the Single-Step Production of Aerial Conidia and Oosporein by Beauveria bassiana PQ2

2021 ◽  
Vol 7 (8) ◽  
pp. 582
Author(s):  
Héctor Raziel Lara-Juache ◽  
José Guadalupe Ávila-Hernández ◽  
Luis Víctor Rodríguez-Durán ◽  
Mariela Ramona Michel ◽  
Jorge Enrique Wong-Paz ◽  
...  
Keyword(s):  
Biological Control ◽  
Antifungal Activity ◽  
Secondary Metabolites ◽  
Beauveria Bassiana ◽  
Single Step ◽  
Agricultural Pest ◽  
Simultaneous Production ◽  
Pest Insects ◽  
Aerial Conidia

Beauveria bassiana is an entomopathogenic fungus that is used for the biological control of different agricultural pest insects. B. bassiana is traditionally cultivated in submerged fermentation and solid-state fermentation systems to obtain secondary metabolites with antifungal activity and infective spores. This work presents the design and characterization of a new laboratory-scale biofilm bioreactor for the simultaneous production of oosporein and aerial conidia by B. bassiana PQ2. The reactor was built with materials available in a conventional laboratory. KLa was determined at different air flows (1.5–2.5 L/min) by two different methods in the liquid phase and in the exhaust gases. The obtained values showed that an air flow of 2.5 L/min is sufficient to ensure adequate aeration to produce aerial conidia and secondary metabolites by B. bassiana. Under the conditions studied, a concentration of 183 mg oosporein per liter and 1.24 × 109 spores per gram of support was obtained at 168 h of culture. These results indicate that the biofilm bioreactor represents a viable alternative for the production of products for biological control from B. bassiana.

scholarly journals Isolation and characterization of a high iturin yielding Bacillus velezensis UV mutant with improved antifungal activity

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0234177
Author(s):  
Young Tae Kim ◽  
Sung Eun Kim ◽  
Won Jung Lee ◽  
Zhao Fumei ◽  
Min Sub Cho ◽  
...  
Keyword(s):  
Biological Control ◽  
Antifungal Activity ◽  
Mutant Strain ◽  
Fusarium Wilt ◽  
Potential Candidate ◽  
Wild Type ◽  
Bacillus Velezensis ◽  
Sclerotinia Rot ◽  
Isolation And Characterization

To isolate Bacillus velezensis mutants with improved antifungal activity for use in the biological control of phytopathogenic fungi, wild-type Bacillus velezensis KRF-001 producing iturin, surfactin, and fengycin was irradiated by ultraviolet (UV) rays. The in vitro and in vivo antifungal activities of UV mutants and characterization of the cyclic lipopeptides produced by a selected mutant were examined. A mutant strain yielding high levels of iturin showed over 2-fold higher antifungal activity than the wild-type against Fusarium oxysporum. A potent suppressive effect of the mutant was also observed on spore germination of Botrytis cinerea, the causative agent of cucumber gray mold, at different butanol extract concentrations. Further analysis of the mutant by real-time PCR and high-performance liquid chromatography revealed increased expression of iturin and surfactin biosynthesis genes as well as enhanced production of iturin and surfactin metabolites. However, the amounts of fengycin obtained from the mutant strain BSM54 were significantly lesser than those of iturin and surfactin. Particularly, iturin A production by the mutant was 3.5-fold higher than that of the wild-type, suggesting that the higher antifungal activity of the mutant against F. oxysporum resulted from the increased expression of biosynthesis genes associated with iturin production. The commercial greenhouse experiment using soil naturally infested with Sclerotinia sclerotiorum (sclerotinia rot) and F. oxysporum (fusarium wilt) showed that the mutant strain reduced sclerotinia rot and fusarium wilt diseases (P = 0.05) more effectively than the wild-type and commercially available product Cillus® in Korea. These results suggest that the mutant with high iturin yield is a potential candidate for the development of a biological control agent in agriculture.

A p-Type PbS Quantum Dot Ink with Improved Stability for Solution Processable Optoelectronics

2021 ◽  
Author(s):  
Fiaz Ahmed ◽  
John Hardin Dunlap ◽  
Perry J. Pellechia ◽  
Andrew Greytak
Keyword(s):  
Quantum Dot ◽  
Ligand Exchange ◽  
Chemical Characterization ◽  
Single Step ◽  
Improved Stability ◽  
Solution Processable ◽  
P Type ◽  
Pbs Quantum Dot

A highly stable p-type PbS-QDs ink is prepared using a single-step biphasic ligand exchange route, overcoming instability encountered in previous reports. Chemical characterization of the ink reveals 3-mercaptopriopionic acid (MPA)...

scholarly journals Synthesis and Polymerization Kinetics of Rigid Tricyanate Ester

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1686
Author(s):  
Andrey Galukhin ◽  
Roman Nosov ◽  
Ilya Nikolaev ◽  
Elena Melnikova ◽  
Daut Islamov ◽  
...  
Keyword(s):  
Kinetic Analysis ◽  
Single Step ◽  
Polymerization Kinetics ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Diffusion Controlled ◽  
Polymerization Product ◽  
The One ◽  
Kinetics Of

A new rigid tricyanate ester consisting of seven conjugated aromatic units is synthesized, and its structure is confirmed by X-ray analysis. This ester undergoes thermally stimulated polymerization in a liquid state. Conventional and temperature-modulated differential scanning calorimetry techniques are employed to study the polymerization kinetics. A transition of polymerization from a kinetic- to a diffusion-controlled regime is detected. Kinetic analysis is performed by combining isoconversional and model-based computations. It demonstrates that polymerization in the kinetically controlled regime of the present monomer can be described as a quasi-single-step, auto-catalytic, process. The diffusion contribution is parameterized by the Fournier model. Kinetic analysis is complemented by characterization of thermal properties of the corresponding polymerization product by means of thermogravimetric and thermomechanical analyses. Overall, the obtained experimental results are consistent with our hypothesis about the relation between the rigidity and functionality of the cyanate ester monomer, on the one hand, and its reactivity and glass transition temperature of the corresponding polymer, on the other hand.

A Single Step Synthesis By Mechanical Alloying and Characterization of Nanostructured Fe2B of High Magnetic Moment

2021 ◽  
Author(s):  
Telem Şimşek ◽  
Barış Avar ◽  
Tuncay Şimşek ◽  
Buğra Yıldız ◽  
Arun K. Chattopadhyay ◽  
...  
Keyword(s):  
Mechanical Alloying ◽  
Magnetic Moment ◽  
Single Step ◽  
High Magnetic Moment
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