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Actinobacteria obtained from the least explored Indian regions were studied for their ability to suppress meningitis-causing bacteria in nanoparticle form. Drug-resistant bacteria and long-term treatment with different medications make meningitis control complicated. Thus, new meningitis drugs are required to combat MDR bacteria. In this study, secondary metabolites isolated from actinomycetes strains, Microbacterium proteolyticum LA2(R) and Streptomyces rochei LA2(O), were employed to synthesize silver nanoparticles (AgNPs) at 37 °C for seven days incubation. UV–Vis spectroscopy, TEM, FTIR, and HPLC studies were used for the confirmation of the synthesis of AgNPs. Furthermore, these NPs demonstrated antibacterial and antibiofilm activities against meningitis-causing bacteria. The average size of LA2(R) and LA2(O) isolated secondary metabolites mediated AgNPs was observed to be 27 ± 1and 29 ± 2 nm by TEM analysis. FTIR study of RAgNPs and OAgNPs revealed that presence of peaks with positions of 1637.17 cm1 and 1636.10 cm1 for C=O amide group appearances in the amide I linkage. These NPs were effective against bacterial pathogens such as S. pneumoniae, H. influenzae, and N. meningitidis and confirmed by their MICs, i.e., 109.4, 120.60, and 138.80 μg/ml of RAgNPs and 105.80, 114.40 and 129.06 μg/ml of OAgNPs, respectively. Additionally, the production of biofilms is impeded by these nanoparticles on S. pneumoniae, H. influenzae, and N. meningitidis by 73.14%, 71.89% and 64.81%, respectively. These findings confirm the potential role of synthesized AgNPs against biofilm forming meningitis causing Multidrug resistance (MDR) microbes.

Bioplastics, synthesized by several microbes, accumulates inside cells under stress conditions as a storage material. Several microbial enzymes play a crucial role in their degradation. This research was carried to test the biodegradability of poly-β-hydroxybutyrate (PHB) utilizing PHB depolymerase, produced by bacteria isolated from sewage waste soil samples. Potent PHB degrader was screened based on the highest zone of hydrolysis followed by PHB depolymerase activity. Soil burial method was employed to check their degradation ability at different incubation periods of 15, 30, and 45 days at 37±2°C, pH 7.0 at 60% moisture with 1% microbial inoculum of Aeromonas caviae Kuk1-(34) (MN414252). Without optimized conditions, 85.76% of the total weight of the PHB film was degraded after 45 days. This degradation was confirmed with Fourier-transform infrared spectroscopy (FTIR) and Scanning electron microscope (SEM) analysis. The presence of bacterial colonies on the surface of the degraded film, along with crest, holes, surface erosion, and roughness, were visible. Media optimization was carried out in statistical mode using Plackett Burman (PB) and Central Composite Design (CCD) of Response Surface Methodology (RSM) by considering ten different factors. Analysis of Variance (ANOVA), Pareto chart, response surface plots, and F-value of 3.82 implies that the above statistical model was significant. The best production of PHB depolymerase enzyme (14.98 U/mL) was observed when strain Kuk1-(34) was grown in a media containing 0.1% PHB, K2HPO4 (1.6 gm/L) at 27 ℃ for seven days. Exploiting these statistically optimized conditions, the culture was found to be a suitable candidate for the management of solid waste, where 94.4% of the total weight of the PHB film was degraded after 45 days of incubation.