Influence of pH and Impeller Tip Speed onthe Cultivation of Bifidobacterium pseudocatenulatum G4 in a Milk-Based Medium

A. M. Yazid,W. Stephenie,B. M. Kabeir,M. Shuhaimi,M. Rosfarizan 한국생물공학회 2007 Biotechnology and Bioprocess Engineering Vol.12 No.5

Biomass production of Bifidobacterium pseudocatenulatum G4 in a milk-based medium was carried out in a 2- and 10-L stirred tank fermenters. The effects of impeller tip speed (0.28, 0.56, and 0.83 m/s) and pH control (6.0, 6.5, and 7.0) on the biomass production were investigated. The growth performance in the 2-L fermenter was significantly improved when the impeller tip speed was held constant at 0.56 m/s and the pH was controlled at 6.5. These conditions yielded a maximum biomass of 1.687 × 109 cfu/mL, a maximum specific growth rate of 0.504 h-1, a biomass productivity of 9.240 × 107 cfu/mL·h, and a biomass yield of 9.791 × 1010 cfu/g lactose. The consumption of milk lactose resulted in the accumulation of 7.353 g/L acetic acid and 6.515 g/L lactic acid, with an acetic:lactic ratio of 1.129. Scale-up of the fermentation process to a 10-L fermenter based on a constant impeller tip speed of 0.56 m/s yielded reproducible results with respect to biomass production and cell viability.

Influence of pH and Impeller Tip Speed on the Cultivation of Bifidobacterium Pseudocatenulatum G4 in a Milk-Based Medium

Stephenie, W.,Kabeir, B.M.,Shuhaimi, M.,Rosfarizan, M.,Yazid, A.M. Korean Society for Biotechnology and Bioengineerin 2007 Biotechnology and Bioprocess Engineering Vol.12 No.5

Biomass production of Bifidobacterium pseudocatenulatum G4 in a milk-based medium was carried out in a 2- and 10-L stirred tank fermenters. The effects of impeller tip speed (0.28, 0.56, and 0.83 m/s) and pH control (6.0, 6.5, and 7.0) on the biomass production were investigated. The growth performance in the 2-L fermenter was significantly improved when the impeller tip speed was heId constant at 0.56 m/s and the pH was controlled at 6.5. These conditions yielded a maximum biomass of $1.687{\times}10^9cfu/mL$, a maximum specific growth rate of $0.504 h^{-1}$, a biomass productivity of $9.240{\times}10^7 cfu/mL{\cdot}h$, and a biomass yield of $9.791{\times}10^{10} cfu/g$ lactose. The consumption of milk lactose resulted in the accumulation of 7.353 g/L acetic acid and 6.515 g/L lactic acid, with an acetic:lactic ratio of 1.129. Scale-up of the fermentation process to a 10-L fermenter based on a constant impeller tip speed of 0.56 m/s yielded reproducible results with respect to biomass production and cell viability.

Simulation study of magnetorheological testing cell design by incorporating all basic operating modes

Mohd J. Mughni,Saiful A. Mazlan,Izyan I.M. Yazid,Mohd A.A. Rahman,Hairi Zamzuri 국제구조공학회 2014 Smart Structures and Systems, An International Jou Vol.14 No.5

Magnetorheological (MR) fluid is one of the field-responsive fluids that is of interest to many researchers due to its high yield stress value, which depends on the magnetic field strength. Similar to electrorheological (ER) fluid, the combination of working modes is one of the techniques to increase the performance of the fluids with limited focus on MR fluids. In this paper, a novel MR testing cell incorporated with valve, shear and squeeze operational modes is designed and constructed in order to investigate the behaviour of MR fluid in combined mode. The magnetic field distribution in the design concept was analyzed using finite element method in order to verify the effective areas of each mode have the acceptable range of flux density. The annular gap of valve and shear were fixed at 1 mm, while the squeeze gap between the parallel circular surfaces was varied up to 20 mm. Three different coil configurations, which were made up from 23 SWG copper wires were set up in the MR cell. The simulation results indicated that the magnetic field distributed in the squeeze gap was the highest among the other gaps with all coils were subjected to a constant applied current of 1 A. Moreover, the magnetic flux densities in all gaps were in a good range of magnitude based on the simulations that validated the proposed design concept. Hence, the 3D model of the MR testing cell was designed using Solidworks for manufacturing processes.

Simulation study of magnetorheological testing cell design by incorporating all basic operating modes

Mughni, Mohd J.,Mazlan, Saiful A.,Zamzuri, Hairi,Yazid, Izyan I.M.,Rahman, Mohd A.A. Techno-Press 2014 Smart Structures and Systems, An International Jou Vol.14 No.5

Magnetorheological (MR) fluid is one of the field-responsive fluids that is of interest to many researchers due to its high yield stress value, which depends on the magnetic field strength. Similar to electrorheological (ER) fluid, the combination of working modes is one of the techniques to increase the performance of the fluids with limited focus on MR fluids. In this paper, a novel MR testing cell incorporated with valve, shear and squeeze operational modes is designed and constructed in order to investigate the behaviour of MR fluid in combined mode. The magnetic field distribution in the design concept was analyzed using finite element method in order to verify the effective areas of each mode have the acceptable range of flux density. The annular gap of valve and shear were fixed at 1 mm, while the squeeze gap between the parallel circular surfaces was varied up to 20 mm. Three different coil configurations, which were made up from 23 SWG copper wires were set up in the MR cell. The simulation results indicated that the magnetic field distributed in the squeeze gap was the highest among the other gaps with all coils were subjected to a constant applied current of 1 A. Moreover, the magnetic flux densities in all gaps were in a good range of magnitude based on the simulations that validated the proposed design concept. Hence, the 3D model of the MR testing cell was designed using Solidworks for manufacturing processes.

Growth Optimization of a Probiotic Candidate, Bifidobacterium pseudocatenulatum G4, in Milk Medium Using Response Surface Methodology

A. M. Yazid,W. Stephenie,B. M. Kabeir,M. Shuhaimi,M. Rosfarizan 한국생물공학회 2007 Biotechnology and Bioprocess Engineering Vol.12 No.2

Bifidobacterium pseudocatenulatum G4, a wild strain isolated from infant stools that has previously exhibited probiotic characteristics, was used in this study. The aim of this research was to improve the growth potential of this strain in milk-based medium. An initial screening study using a 23 full factorial design was carried out to identify the impact on biomass production of the various components of the medium which were skim milk, yeast extract, and glucose. Statistical analysis suggested that yeast extract had a significant positive effect on viable cell count whereas glucose had a negative effect. Response surface methodology (RSM) was then applied to optimize the use of skim milk and yeast extract. A quadratic model was derived using a 32 face-centered central composite design to represent cell mass as a function of the two variables. The optimized medium composition was found to be 2.8% skim milk and 2.2% yeast extract, w/v. The optimized medium allowed a maximum biomass of 9.129 log10 cfu/mL, 3.329 log units higher than that achieved with 10% skim milk, which is the amount commonly used. The application of RSM resulted in an improvement in the biomass production of this strain in a more cost-effective milk medium, in which skim milk use was reduced by 71.8%.

Growth Optimization of a Probiotic Candidate, Bifidobacterium Pseudocatenulatum G4, in Milk Medium Using Response Surface Methodology

Stephenie, W.,Kabeir, B.M.,Shuhaimi, M.,Rosfarizan, M.,Yazid, A.M. Korean Society for Biotechnology and Bioengineerin 2007 Biotechnology and Bioprocess Engineering Vol.12 No.2

Bifidobacterium pseudocatenulatum G4, a wild strain isolated from infant stools that has previously exhibited probiotic characteristics, was used in this study. The aim of this research was to improve the growth potential of this strain in milk-based medium. An initial screening study using a $2^3$ full factorial design was carried out to identify the impact on biomass production of the various components of the medium which were skim milk, yeast extract, and glucose. Statistical analysis suggested that yeast extract had a significant positive effect on viable cell count whereas glucose had a negative effect. Response surface methodology (RSM) was then applied to optimize the use of skim milk and yeast extract. A quadratic model was derived using a $3^2$ face-centered central composite design to represent cell mass as a function of the two variables. The optimized medium composition was found to be 2.8% skim milk and 2.2% yeast extract, w/v. The optimized medium allowed a maximum biomass of 9.129 $log_{10}cfu/mL$, 3.329log units higher than that achieved with 10% skim milk, which is the amount commonly used. The application of RSM resulted in an improvement in the biomass production of this strain in a more cost-effective milk medium, in which skim milk use was reduced by 71.8%.

Magnetic circuit optimization in designing Magnetorheological damper

Yazid, Izyan I.M.,Mazlan, Saiful A.,Kikuchi, Takehito,Zamzuri, Hairi,Imaduddin, Fitrian Techno-Press 2014 Smart Structures and Systems, An International Jou Vol.14 No.5

This paper presents the materials analysis for combination of working modes of Magnetorheological (MR) damper. The materials were selected based on the optimum magnetic field strength at the effective areas in order to obtain a better design of MR damper. The design of electromagnetic circuit is one of the critical criteria in designing MR dampers besides the working mechanism and the types of MR damper. The increase in the magnetic field strength is an indication of the improvement in the damping performance of the MR damper. Eventually, the experimental test was performed under quasi-static loading to observe the performances of MR damper in shear mode, squeeze mode and mixed mode. The results showed that the increment of forces was obtained with the increased current due to higher magnetic flux density generated by electromagnetic coils. In general, it can be summarized that the combination of modes generates higher forces than single mode for the same experimental parameters throughout the study.

Anti-tumor Promoting Activity of Some Malaysian Traditional Vegetable (Ulam) Extracts by Immunoblotting Analysis of Raji Cells

A. M. Ali,L. Y. Mooi,K. Yih Yih,A. W. Norhanom,K. Mat Saleh,N. H. Lajis,A. M. Yazid,F. B. H. Ahmad,U. Prasad 한국생약학회 2000 Natural Product Sciences Vol.6 No.3

The extracts of Carica papaya (flower), Barringtonia macrostachya (leaves), Coleus tuberosus (tuber), Mangifera indica (fruit skin) and Eugenia polyantha (leaves) showed strong in vitro anti-tumor promoting activity when assayed using Raji cells (Mooi et al., 1999). The anti-tumor promoting activity of the crude extracts was further analyzed by immunoblotting analysis of Raji cells carrying Epstein-Barr virus genome. The expression of early antigens diffuse (EA-D) and early antigens restricted (EA-R) was determined by performing western blotting of treated Raji cells with human sera of nasopharyngeal carcinoma patients. All the plant extracts were shown to be able to suppress both EA-D and EA-R.

Antihypertensive and Cardiovascular Effects of Catechin-Rich Oil Palm (Elaeis guineensis) Leaf Extract in Nitric Oxide–Deficient Rats

Juliana M. Jaffri,Suhaila Mohamed,Nordanial Rohimi,Intan N. Ahmad,M. Mustapha Noordin,Yazid A. Manap 한국식품영양과학회 2011 Journal of medicinal food Vol.14 No.7

Oil palm (Elaeis guineensis) leaf extract (OPLE) possesses good ex vivo vasodilation and antioxidant properties. This study evaluated the catechin-rich OPLE antioxidant, antihypertensive, and cardiovascular effects in normal and nitric oxide (NO)–deficient hypertensive rats. OPLE was administered orally (500 mg/kg of body weight/day) to normotensive Wistar rats and Nω-nitro-l-arginine methyl ester (l-NAME)-induced NO-deficient hypertensive rats. OPLE significantly (P<.05) attenuated blood pressure increases, increased serum NO, reduced lipid peroxidation, and showed antioxidant effects in NO-deficient hypertensive rats. OPLE decreased the coronary arteriole wall-to-lumen ratio to near normal values under NO deficiency. Although OPLE showed good antihypertensive and antioxidant effects under NO deficiency, it was not hypotensive to normal rats and produced no chronic cardiovascular toxicity in any of the rats throughout the 12-week study. This is the first report on the in vivo antihypertensive properties of green tea catechins extracted from an alternative source, namely, oil palm leaf, for use as a medicinal food for hypertension and cardiovascular ailments.

Magnetic circuit optimization in designing Magnetorheological damper

Izyan I.M. Yazid,Saiful A. Mazlan,Fitrian Imaduddin,Takehito Kikuchi,Hairi Zamzuri 국제구조공학회 2014 Smart Structures and Systems, An International Jou Vol.14 No.5

This paper presents the materials analysis for combination of working modes of Magnetorheological (MR) damper. The materials were selected based on the optimum magnetic field strength at the effective areas in order to obtain a better design of MR damper. The design of electromagnetic circuit is one of the critical criteria in designing MR dampers besides the working mechanism and the types of MR damper. The increase in the magnetic field strength is an indication of the improvement in the damping performance of the MR damper. Eventually, the experimental test was performed under quasi-static loading to observe the performances of MR damper in shear mode, squeeze mode and mixed mode. The results showed that the increment of forces was obtained with the increased current due to higher magnetic flux density generated by electromagnetic coils. In general, it can be summarized that the combination of modes generates higher forces than single mode for the same experimental parameters throughout the study.