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Nitrogen removal in moving bed sequencing batch reactor using polyurethane foam cubes of various sizes as carrier materials

Lim JW, Seng CE, Lim PE, Ng SL, Sujari AN

Bioresour Technol, 2011 Nov;102(21):9876-83.
PMID: 21890353 DOI: 10.1016/j.biortech.2011.08.014

The performance of moving bed sequencing batch reactors (MBSBRs) added with 8 % (v/v) of polyurethane (PU) foam cubes as carrier media in nitrogen removal was investigated in treating low COD/N wastewater. The results indicate that MBSBR with 8-mL cubes achieved the highest total nitrogen (TN) removal efficiency of 37% during the aeration period, followed by 31%, 24% and 19 % for MBSBRs with 27-, 64- and 125-mL cubes, respectively. The increased TN removal in MBSBRs was mainly due to simultaneous nitrification and denitrification (SND) process which was verified by batch studies. The relatively lower TN removal in MBSBR with larger PU foam cubes was attributed to the observation that larger PU foam cubes were not fully attached by biomass. Higher concentrations of 8-mL PU foam cubes in batch reactors yielded higher TN removal.

Matched MeSH terms: Batch Cell Culture Techniques/instrumentation*
Simultaneous 4-chlorophenol and nitrogen removal in moving bed sequencing batch reactors packed with polyurethane foam cubes of various sizes

Lim JW, Lim PE, Seng CE, Adnan R

Bioresour Technol, 2013 Feb;129:485-94.
PMID: 23266850 DOI: 10.1016/j.biortech.2012.11.111

Moving bed sequencing batch reactors (MBSBRs) packed with 8% (v/v) of 8-, 27- and 64-mL polyurethane (PU) foam cubes, respectively, were investigated for simultaneous 4-chlorophenol (4-CP) and nitrogen removal at increasing 4-CP concentration. When the 4-CP concentration exceeded 300 mg L(-1), the MBSBR with 27-mL foam cubes was observed to outperform the other MBSBRs in removing 4-CP and nitrogen. The reasons were: (1) there were more biomass in inner layer of the 27-mL cubes, compared to that of the 8-mL cubes, which was more shielded from the inhibitory effect of 4-CP and (2) the 27-mL cubes were more mobile than the 64-mL cubes. Although increasing 4-CP concentration to 600 mg L(-1) resulted in incomplete removal of 4-CP in the MBSBRs, results of the batch reactor with 27-mL foam cubes showed that complete 4-CP removal within the REACT period could be achieved by increasing the packing volume to 20%.

Matched MeSH terms: Batch Cell Culture Techniques/instrumentation*
Fulltext Bioprocess optimization for pectinase production using Aspergillus niger in a submerged cultivation system

El Enshasy HA, Elsayed EA, Suhaimi N, Malek RA, Esawy M

BMC Biotechnol, 2018 11 09;18(1):71.
PMID: 30413198 DOI: 10.1186/s12896-018-0481-7

BACKGROUND: Pectinase enzymes present a high priced category of microbial enzymes with many potential applications in various food and oil industries and an estimated market share of $ 41.4 billion by 2020.
RESULTS: The production medium was first optimized using a statistical optimization approach to increase pectinase production. A maximal enzyme concentration of 76.35 U/mL (a 2.8-fold increase compared with the initial medium) was produced in a medium composed of (g/L): pectin, 32.22; (NH4)2SO4, 4.33; K2HPO4, 1.36; MgSO4.5H2O, 0.05; KCl, 0.05; and FeSO4.5H2O, 0.10. The cultivations were then carried out in a 16-L stirred tank bioreactor in both batch and fed-batch modes to improve enzyme production, which is an important step for bioprocess industrialization. Controlling the pH at 5.5 during cultivation yielded a pectinase production of 109.63 U/mL, which was about 10% higher than the uncontrolled pH culture. Furthermore, fed-batch cultivation using sucrose as a feeding substrate with a rate of 2 g/L/h increased the enzyme production up to 450 U/mL after 126 h.
CONCLUSIONS: Statistical medium optimization improved volumetric pectinase productivity by about 2.8 folds. Scaling-up the production process in 16-L semi-industrial stirred tank bioreactor under controlled pH further enhanced pectinase production by about 4-folds. Finally, bioreactor fed-batch cultivation using constant carbon source feeding increased maximal volumetric enzyme production by about 16.5-folds from the initial starting conditions.

Matched MeSH terms: Batch Cell Culture Techniques/instrumentation
Long term mesenchymal stem cell culture on a defined synthetic substrate with enzyme free passaging

Duffy CR, Zhang R, How SE, Lilienkampf A, De Sousa PA, Bradley M

Biomaterials, 2014 Jul;35(23):5998-6005.
PMID: 24780167 DOI: 10.1016/j.biomaterials.2014.04.013

Mesenchymal stems cells (MSCs) are currently the focus of numerous therapeutic approaches in tissue engineering/repair because of their wide multi-lineage potential and their ability to modulate the immune system response following transplantation. Culturing these cells, while maintaining their multipotency in vitro, currently relies on biological substrates such as gelatin, collagen and fibronectin. In addition, harvesting cells from these substrates requires enzymatic or chemical treatment, a process that will remove a multitude of cellular surface proteins, clearly an undesirable process if cells are to be used therapeutically. Herein, we applied a high-throughput 'hydrogel microarray' screening approach to identify thermo-modulatable substrates which can support hES-MP and ADMSC growth, permit gentle reagent free passaging, whilst maintaining multi-lineage potential. In summary, the hydrogel substrate identified, poly(AEtMA-Cl-co-DEAA) cross-linked with MBA, permitted MSCs to be maintained over 10 passages (each time via thermo-modulation), with the cells retaining expression of MSC associated markers and lineage potency. This chemically defined system allowed the passaging and maintenance of cellular phenotype of this clinically important cell type, in the absence of harsh passaging and the need for biological substrates.

Matched MeSH terms: Batch Cell Culture Techniques/instrumentation*
Influence of agitation speed on tannase production and morphology of Aspergillus niger FETL FT3 in submerged fermentation

Darah I, Sumathi G, Jain K, Lim SH

Appl Biochem Biotechnol, 2011 Dec;165(7-8):1682-90.
PMID: 21947762 DOI: 10.1007/s12010-011-9387-8

Agitation speed was found to influence the tannase production and fungal growth of Aspergillus niger FETL FT3. The optimal agitation speed was at 200 rpm which produced 1.41 U/ml tannase and 3.75 g/l of fungal growth. Lower or higher agitation speeds than 200 rpm produced lower enzyme production and fungal growth. Based on the SEM and TEM micrograph observation, there was a significant correlation between agitation speed and the morphology of the fungal mycelia. The results revealed an increase of the enzyme production with the change of the fungal growth morphology from filamentous to pelleted growth forms. However, the exposure to higher shear stress with an increasing agitation speed of the shaker also resulted in lower biomass yields as well as enzyme production.

Matched MeSH terms: Batch Cell Culture Techniques/instrumentation