Chitin derivatives of NAG and chitosan nanoparticles from marine disposal yards and their use for economically feasible fish feed development.

Globally, the disposal of shellfishery waste is a major challenge and causes a risk to the coastal region. For potential development in aquaculture, the use of safe supplements to improve fish production and health is important. Chitosan (CS) used as feed additives for several fish species that enhanced production and immunity. The present study was intended to assess the effect of feed additives N-acetyl-d-glucosamine (NAG) loaded chitosan nanoparticles (CSNPs) on productivity, survival rate, and protein conversion efficiency of Oreochromis niloticus (L.). This is the first report on the effect of CSNPs and NAG loaded CSNPs as feed additives enhanced growth performance and non-specific immunity of O. niloticus. CSNPs and NAG loaded CSNPs were synthesized and characterized by scanning and transmission electron microscope, FT-IR, X-ray diffraction, particle size distribution, and zeta sizer. Fish (15.30 ± 0.23 g) administered diets fortified with 0.0, 0.25, 0.5, 1.0, and 2.0 g CSNPs/kg feed loaded with NAG for 45 d. The diets containing 1.0 g/kg NAG loaded CSNPs enhanced specific growth rate, weight gain, survival rate, respiratory burst, and lysozyme activities of tilapia compared control group. The data shows biologically active CSNPs and NAG loaded CSNPs are potent antimicrobial agents against selected bacterial pathogens. In conclusion, the findings suggested that the dietary supplement containing NAG loaded CSNPs significantly increased immune-modulatory properties, growth performance, and enhanced their disease resistance of Nile tilapia.

Bioconversion of chitin and concomitant production of chitinase and N-acetylglucosamine by novel Achromobacter xylosoxidans isolated from shrimp waste disposal area.

Marine pollution is a significant issue in recent decades, with the increase in industries and their waste harming the environment and ecosystems. Notably, the rise in shellfish industries contributes to tons of shellfish waste composed of up to 58% chitin. Chitin, the second most ample polymer next to cellulose, is insoluble and resistant to degradation. It requires chemical-based treatment or enzymatic hydrolysis to cleave the chitin polymers. The chemical-based treatment can lead to environmental pollution, so to solve this problem, enzymatic hydrolysis is the best option. Moreover, the resulting biopolymer by-products can be used to boost the fish immune system and also as drug delivery agents. Many marine microbial strains have chitinase producing ability. Nevertheless, we still lack an economical and highly stable chitinase enzyme for use in the industrial sector. So we isolate a novel marine bacterial strain Achromobacter xylosoxidans from the shrimp waste disposal site using chitin minimal medium. Placket-Burman and central composite design statistical models for culture condition optimisation predicted a 464.2 U/ml of chitinase production. The culture conditions were optimised for maximum chitinase production recording up to 467 U/ml. This chitinase from the A. xylosoxidans was 100% active at an optimum temperature of 45 °C (withstand up to 55 °C) and pH 8 with 80% stability. The HPLC analysis of chitinase degraded shellfish waste reveals a major amino acid profile composition-arginine, lysine, aspartic acid, alanine, threonine and low levels of isoleucine and methionine. These chitinase degraded products and by-products can be used as supplements in the aquaculture industry.

Actinobacterial-Mediated Fabrication of Silver Nanoparticles and Their Broad Spectrum Antibacterial Activity Against Clinical Pathogens.

The aim of this study is to fabricate silver nanoparticles (AgNPs) using actinobacterial strain isolated from lawn soil. Among six isolates, one isolate named AS-3 was potent in AgNPs production; hence it was identified deployed on gene sequence (16S rRNA) as Streptomyces spongiicola AS-3 (99.8% similarity). Actinobacteria mediated synthesized AgNPs were analyzed using UV-visible spectroscopy (UV-Vis), which showed a Surface Plasmon Resonance (SPR) at around λ = 443 nm. Scanning electron microscopy (SEM) analyses revealed the occurrence of predominant spherical AgNPs with polydispersed, with an average size of 22 nm. Energy-dispersive X-ray spectroscopy (EDS) established the existence of silver component. While the Fourier transforms infrared spectroscopy (FTIR) evidenced the occurrence of proteins as the bio reduction and topping agents over the AgNPs. X-ray diffraction (XRD) examination confirmed the obtained AgNPs were in crystalline planes of the face centric cubic. The S. spongiicola AgNPs antibacterial activity showed a broad spectrum antibacterial action against Staphylococcus aureus, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Vibrio cholera, Shigella sp., and Salmonella typhi were confirmed by disc diffusion test and MIC analysis.