• Biotechnology and Bioprocess Engineering:BBE
• /
• v.10 no.2
• /
• pp.128-135
• /
• 2005

Mixed-mode hydrophobic/ionic matrices exhibit a salt-tolerant property for adsorbing target protein from high-ionic strength feedstock, which allows the application of undiluted feedstock via an expanded bed process. In the present work, a new type of mixed-mode adsorbent designed for expanded bed adsorption, Fastline $PRO^{\circledR}$, was challenged for the capture of nattokinase from the high ionic fermentation broth of Bacillus subtilis. Two important factors, pH and ion concentration, were investigated with regard to the performance of nattokinase ad-sorption. Under initial fermentation broth conditions (pH 6.6 and conductivity of 10 mS/cm) the adsorption capacity of nattokinase with Fastline PRO was high, with a maximum capacity of 5,350 U/mL adsorbent. The elution behaviors were investigated using packed bed adsorption experiments, which demonstrated that the effective desorption of nattokinase could be achieved by effecting a pH of 9.5. The biomass pulse response experiments were carried out in order to evaluate the biomass/adsorbent interactions between Bacillus subtilis cells and Fastline PRO, and to demonstrate a stable expanded bed in the feedstock containing Bacillus subtilis cells. Finally, an EBA process, utilizing mixed-mode Fastline PRO adsorbent, was optimized to capture nattokinase directly from the fermentation broth. The purification factor reached 12.3, thereby demonstrating the advantages of the mixed-mode EBA in enzyme separation.

• Journal of Microbiology and Biotechnology
• /
• v.9 no.3
• /
• pp.292-296
• /
• 1999

The high density mixed mode adsorbent known by the trade name of Mimo-AD was used to purify lysozyme directly from the hen egg white (HEW). The homogenized hen egg white was treated with the adsorbent in a stirred vessel for lysozyme adsorption, and then the adsorbent, easily separated from the HEW by sedimentation, was packed into a column. The remaining HEW and contaminant proteins were removed by washing with pH 11 distilled water in an expanded-bed state, and subsequently the elution was performed with pH 12 distilled water in a packed-bed state. By this simple and rapid adsorption, washing, and elution procedure, lysozyme was purified to＞95％ with an overall recovery yield of 66％. This process offers a great potential for industrial application by allowing the extraction of lysozyme while retaining the commercial value of HEW.

• Environmental Engineering Research
• /
• v.19 no.3
• /
• pp.205-214
• /
• 2014

Petroleum a vital commodity affecting every aspect of 21st century. Toxicity and adverse effects of sulphur as catalyst in petroleum products is of great concern required development of techniques for desulphurization in compliance with the International standards. Installation of desulphurizing units costs over $200 million per unit placing economic burden on developing countries like Pakistan. Present study analysis of commercial fuels (station petrol and jet fuel JP8) on gas chromatography-mass spectrometry (GC-MS) identified sulphur concentration of 19.94 mg/L and 21.75 mg/L, respectively. This scenario urged the researcher to attempt synthesis of material that is likely to offer good adsorption capacity for sulphur. Following protocol of sol-gel method, transition metals (Ni, Cu, Zn) solution is gelated with tetraethoxysilane (TEOS; silica precursor) using glycerol. Fourier transform infrared spectroscopy (FTIR) spectra revealed bonding of Zn-O, Cu-O, and Ni-O by stretching vibrations at $468cm^{-1}$, $617cm^{-1}$, and $468cm^{-1}$, respectively. Thiophene and Benzothiophene mixed in n-heptane and benzene (4:1) for preparation of Model Fuels I and II, respectively. Each of silica based metal was applied as adsorbent in batch mode to assess the removal efficiency. Results demonstrated optimal desulphurization of more than 90% following efficacy order as Si-Ni > Si-Zn > Si-Cu based adsorbents. Proposed multilayered (Freundlich) adsorption mechanism follows ${\pi}$-complexation with pseudo secnd order kinetics.

• Membrane Journal
• /
• v.17 no.3
• /
• pp.269-275
• /
• 2007

Sodium type faujasite(FAU) zeolite membranes with a thickness of 5${\mu}m$ and a Si/Al molar ratio of 1.5 were prepared by the secondary growth process. The $CO_2/N_2$ separation in the vacuum mode was investigated at $30^{\circ}C$ for an equimolar $CO_2-N_2$ mixed gas before and after embedding 13X zeolite beads in the permeate side. The embedded 13X zeolite beads improved both $CO_2$ permeance and $CO_2/N_2$ separation factor, simultaneously. The phenomenon was explained by an increment in the $CO_2$ desorption rate at the FAU zeolite/$\alpha-Al_2O_3$ phase boundary due to an enhanced $CO_2$ escaping through the pore channels of the $\alpha-Al_2O_3$ support layer. In the present paper, it will be emphasized that a hybridization of a membrane with an adsorbent can provide a key to break through the trade-off between permeance and separation factor, generally shown in a membrane separation.