Lignosulfonic Acid Based Hydrogel Nanocomposites for Antimicrobial Application.

Hydrogels in which poly(acryl amide)/lignosulfonic acid (AAm/LSA) crosslinked with N,N’-methylene bis acrylamide, were prepared by using a redox polymerization technique. These hydrogel networks can act as excellent nano reactors for producing and stabilizing the metal nanoparticles. The current methodology allows us to entrap metal nanoparticles throughout hydrogel networks via AAm/ LSA chains. The synthesized silver nano composite hydrogels (Ag-NCHs) were fully characterized by using UV-visible spectroscopy; Fourier transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD) studies, scanning electron microscopy (SEM), dynamic light scattering (DLS) analysis and Transmission electron microscopy (TEM). The chemical structure and crosslinking in AAm/LSA hydrogels and Ag-NCHs matrix was analyzed by FTIR. SEM and TEM measurements suggested the spherical structure of the silver particles with smooth surface and size of these particles confirmed by DLS. Crystalline nature of the nanoparticles was confirmed by XRD and electron diffraction measurements. Swelling studies were performed in water with the help of an empirical equation to investigate the diffusion mechanism. The developed Ag-NCHs were evaluated for preliminary antibacterial applications against E.coli and Bacillus.

Degradation of lignosulfonic and tannic acids by ligninolytic soil fungi cultivated under icroaerobic conditions

Soil fungi were evaluated regarding their ability to degrade lignin-related compounds by producing the ligninolytic enzymes. Lignosulfonic and tannic acids were used as sole carbon sources during 30 days under microaerobic and very-low-oxygen conditions. The fungi produced lignin-peroxidase, manganese-peroxidase and laccase . Expressive degradations was observed by C18 reversed-phase HPLC, indicating the biodegradation potential of these fungi, showing more advantages than obligate anaerobes to decontaminate the environment when present naturally.

Fungos isolados de solo foram avaliados quanto à habilidade em degradarem compostos derivados de lignina pela produção de enzimas ligninolíticas. Os ácidos lignosulfônicos e tânico foram usados separadamente como única fonte de carobono para cultivo dos fungos em 30 dias sob condições microaeróbias. Os fungos foram capazes de crescer e usar tais compostos como fonte de carbono e mostraram produção de lignina-peroxidase, manganês-peroxidase e lacase. Degradações expressivas dos ácidos lignosulfônico e tânico foram verificadas por Cromatografia Liquida de Alta Eficiência (CLAE), indicando grande potencial de uso em processos de biorremediação de macromoléculas aromáticas similares à lignina em ambientes naturais sob condições baixas de oxigenação.