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The effect of Plant Growth Promoting Rhizobacteria (Bacillus sp.) and silver nanoparticles on Zea mays was evaluated. The silver nanoparticles were synthesized from Tagetes erecta (Marigold) leaf and flower extracts, whereas PGPR isolated from spinach rhizosphere. The silver nanoparticles (AgNPs) were purified using ultra centrifugation and were characterized using UV–Vis spectroscopy at gradient wavelength and also by High Resolution Transmission Electron microscopy (HRTEM). The average particles size of AgNPs was recorded approximately 60 nm. Almost all potential isolates were able to produce Indole Acetic Acid (IAA), ammonia and Hydrogen cyanide (HCN), solubilized tricalcium phosphate and inhibited the growth of Macrophomina phaseolina in vitro but the isolate LPR2 was found the best among all. On the basis of 16S rRNA gene sequence, the isolate LPR2 was characterized as Bacillus cereus LPR2. The maize seeds bacterized with LPR2 and AgNPs individually showed a significant increase in germination (87.5%) followed by LPR2 + AgNPs (75%). But the maximum growth of root and shoot of maize plant was observed in seeds coated with LPR2 followed by AgNPs and a combination of both. Bacillus cereus LPR2 and silver nanoparticles enhanced the plant growth and LPR2 strongly inhibited the growth of deleterious fungal pathogen. Therefore, LPR2 and AgNPs could be utilized as bioinoculant and growth stimulator, respectively for maize.

Carbonic anhydrase (CA) is a family of metalloenzymes that has the potential to sequestrate carbon dioxide (CO2) from the environment and reduce pollution. The goal of this study is to apply protein engineering to develop a modified CA enzyme that has both higher stability and activity and hence could be used for industrial purposes. In the current study, we have developed an in silico method to understand the molecular basis behind the stability of CA. We have performed comparative molecular dynamics simulation of two homologous α-CA, one of thermophilic origin (Sulfurihydrogenibium sp.) and its mesophilic counterpart (Neisseria gonorrhoeae), for 100 ns each at 300, 350, 400, and 500 K. Comparing the trajectories of two proteins using different stability-determining factors, we have designed a highly thermostable version of mesophilic α-CA by introducing three mutations (S44R, S139E, and K168R). The designed mutant α-CA maintains conformational stability at high temperatures. This study shows the potential to develop industrially stable variants of enzymes while maintaining high activity.

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