Conventional treatment for esophageal defects involves surgical removal of the defect area and implant conduit tissues. There exist morbidities and mortalities associated with the treatment including fistula and leakage leading to compromise in quality of life. The aim of this study was to optimize a method for complete decellularization of rat esophagus and to solubilize the decellularized extracellular matrix (dECM) proteins to evaluate in vitro properties for scaffold fabrication. For decellularization, rat esophagi were decellularized using 3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS) and sodium dodecyl sulfate (SDS) buffers for 6 h and overnight, respectively. Post decellularization, the tissue was characterized for DNA, glycosaminoglycans, and elastin quantification; H&E and Masson's trichrome staining; scanning electron microscopy; and SDS-PAGE to evaluate the quantity and quality of the obtained dECM. DNA quantification and histological analysis revealed complete decellularization, while the retention of sGAGs and elastin showed the presence of extracellular proteins in the tissue. The SEM analysis revealed proper orientation of the extracellular matrix and significant proteins were retained in the dECM, which will enhance the regenerative potential. The decellularized tissues were biocompatible, exhibited no toxicity and were also soluble, which can be adapted for scaffold fabrication.
Spent mushroom substrate (SMS), the main by-product of mushroom cultivation, is a source of sugars that can be released by saccharification. This work aimed at investigating the enzymatic saccharification of the polysaccharides of the SMS of shiitake (Lentinula edodes) and oyster mushroom (Pleurotus ostreatus) and exploring the lignin extraction from the saccharification residues. First, analytical enzymatic saccharification (AES) with a cellulase cocktail and an experimental hemicellulase-rich preparation was applied. AES revealed higher digestibility of both polysaccharides for shiitake SMS than for oyster mushroom SMS. Using the cellulase cocktail, shiitake SMS resulted in a digestibility above 80% and 70% (w/w) for cellulose and xylan, respectively, while the maximum values for oyster mushroom SMS were 52% and 32% (w/w). The experimental enzyme preparation resulted in lower cellulose digestibility and higher xylan digestibility. Still, the saccharification trend between the two SMS types remained unchanged. To enhance the enzymatic saccharification of oyster mushroom SMS, hydrothermal treatment was applied. The treatment improved the enzymatic digestibility of cellulose by up to 84%. A validation experiment at larger scale showed that hydrothermally treated oyster mushroom SMS had a comparable overall conversion with non-treated shiitake SMS. Following a biorefinery strategy, lignin was extracted from the residues of the preparative enzymatic saccharification using the green solvent γ-valerolactone under different temperatures and holding times. The extracted product contained 98.8% lignin and did not contain cellulose or xylan. The results of this study provide the grounds for biorefinery processes enabling recovery of bioactive compounds, fermentable sugars, and high-quality lignin from SMS.
Anaerobic digestion (AD) is a sustainable technology that converts organic waste into renewable energy while reducing greenhouse gas emissions. Recent studies suggest that adding CO₂ to the AD process can improve methane production through different mechanisms. This review examines four key ways CO₂ supplementation can enhance methane yield: (1) direct conversion of CO₂ into acetate by homoacetogens, (2) direct methanation of CO₂ by hydrogenotrophic methanogens, (3) improved breakdown of organic material due to higher enzyme activity, and (4) better digester conditions through pH regulation and reduced ammonia toxicity. By analyzing microbial interactions and process improvements, this paper highlights knowledge gaps and the need for further research to optimize CO₂ addition in different operational settings. These findings are expected to contribute to the development of cost-effective and efficient AD systems that support energy recovery and environmental sustainability.
Seventeen halotolerant bacteria were isolated from the Muthupettai mangroves, Tamil Nadu, India, with eight exhibiting protease production. The most potent isolate, VITGS4, identified as Streptomyces sp. via polyphasic taxonomy, yielded 470 U mL-1. Response surface methodology (RSM) optimized protease production by Box-Behnken Design (BBD) using casein (5.5% w/v), pH 7.5, and 9.5 days incubation, achieving 282 U mL-1. The recovered protease was partially purified through acetone precipitation (50% acetone), followed by dialysis, and its purity was estimated through HPLC (high pressure liquid chromatography). Enzyme kinetics revealed a Km of 0.347 µM, a Vo of 0.464 µM min-1, a Vmax of 3.167 µM min-1, and a Kcat of 0.0002 min-1. The enzyme was identified as a halo-thermo-alkaline serine protease, optimally active at pH 8 and 45°C, with activity significantly inhibited by Pb2+ and Hg2+ and enhanced by Zn2+ (95%). Notably, PMSF strongly inhibited protease activity, indicating a serine protease. This protease was successfully employed to recover 726 mg of silver slurry (537 µg mL-1 silver) from X-ray films. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) confirmed the presence of silver (2.2% in the analyzed region), while zeta potential (-26.35 mV) and hydrodynamic diameter (89.94 nm) analyses indicated stable silver nanoparticles. These results demonstrate the potential of marine actinobacteria-derived proteases for efficient silver recovery, offering promising applications in therapeutic and industrial fields.
Fiberbanks are organic-rich sediment deposits in aquatic environments, primarily formed through historical pulp and paper mill activities. These deposits consist of wood-derived fibrous materials and are contaminated with potentially toxic elements (PTEs) such as vanadium, chromium, cobalt, nickel, copper, zinc, arsenic, cadmium, and lead. The leaching of these contaminants into surrounding waters poses significant environmental and health risks, impacting aquatic ecosystems and potentially entering the food chain. Effective remediation of fiberbanks is crucial, particularly in Sweden and other regions with extensive wood-pulping industries. This study aims to evaluate the bioaccumulation capacities of 26 native Swedish white-rot fungi (WRF) species for the remediation of PTEs in fiberbank material. Fiberbank samples were collected from Sundsvall's Bay in the Baltic Sea, while the fungal species were isolated from boreal forests in Västernorrland, Sweden. The fungi were cultured on Hagem agar medium with sterilized fiberbank material as the substrate. After two months, fungal biomass was analyzed for PTE uptake using inductively coupled plasma-mass spectrometry (ICP-MS). The results revealed significant variability (p < 0.001) in PTE uptake among fungal species. Phlebia tremellosa consistently demonstrated the highest bioconcentration factors for analyzed elements, with values for V (0.39), Cr (0.10), Co (1.81), Cu (1.54), Pb (1.65), Ni (1.28), As (0.83), Zn (3.61), and Cd (5.56). Other species, including Laetiporus sulphureus (0.09-4.78), Hymenochaete tabacina (0.08-4.52), and Diplomitoporus crustulinus (0.08-4.48), also exhibited significant bioremediation potential. These findings highlight the potential of native WRF species for PTEs remediation in fiberbanks and provide a foundation for mycoremediation strategies in contaminated environments.
