A recent study by the current authors found simultaneous decolourization and mineralization of high concentrations of methyl orange (500 mg/L) in an anoxic up-flow reactor in denitrifying conditions. To supplement this work, various batch reactor studies were carried out to study the effect of (i) pH (4 to 9), (ii) salinity (1 g/L NaCl to 10 g/L NaCl), (iii) dye concentration (100 mg/L to 1000 mg/L), (iv) biomass concentration (0.3 g/L to 0.21 g/L); on the process, and (iv) kinetics of decolourization in denitrifying conditions. The adapted mixed microbial consortium, originally sourced from the activated sludge process, was capable to simultaneously remove colour, COD, and NO3−-N under denitrifying conditions, even at high methyl orange (MO) concentrations of 1000 mg/L at 84 h. Although the decolourization was possible for wide ranges of pH, better performance was obtained at alkaline pH levels. The decolourization performance increased when biomass concentration increased and was not affected by salinity up to 10 g/L NaCl. This may have been due to enhanced lyses of biomass at high salt concentrations. Batch kinetic studies showed that the MO decolourization followed first-order kinetics, with a rate constant of 0.0612 h−1. Results of this study may help in the future application of textile effluent treatments, using a high biomass retention reactor in denitrifying conditions with minimum sludge disposal costs.
Objectives: Placental tissue is an established biomaterial used in many clinical applications. However, its use for tissue engineering purposes has not been fully realized. Though articular cartilage extracellular matrix (ECM)-derived oriented scaffolds for cartilage tissue engineering were developed, resources are a hindrance to its application. In this regard, the present study investigated the feasibility of using intact decellularized human umbilical cord Wharton’s jelly (hUC-WJ) as a new material for chondrocyte carrier in cartilage tissue engineering. The developed hUC-WJ scaffold provides a good microenvironment for the attachment, viability, and delivery of seeded human autologous chondrocytes. It has an advantage over other biomaterials in terms of abundant availability and similar biochemistry to cartilage ECM. Materials and methods: hUC-WJ obtained from fresh human placenta were decellularized and gamma sterilized. Human cartilage tissue was obtained from the patients with a total knee replacement. The chondrocytes were isolated and expanded in-vitro and seeded onto the hUC-WJ scaffold. The efficiency of the decellularized tissue as a delivery system for human cartilage cells was investigated by histology, immunohistochemistry, cell count, flow cytometry, and scanning electron microscopy (SEM). Results: The results showed that the decellularized hUC-WJ scaffold has supported the microenvironment for chondrocyte attachment and viability without losing its phenotype. In addition, the cells were spread through the hUC-WJ scaffold as confirmed by histology and SEM. Conclusion: Based on obtained results, the hUC-WJ scaffold has great potential as a 3D scaffold for human autologous chondrocyte carriers in tissue engineering and regenerative medicine applications.
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