CATHERINE SM A

Coating of probiotic bacteria to improve storage stability.

 The use of probiotic cells in animal feed has been expanding rapidly due to the increasing demand for safer food. Long-term survival of cells has been put at a premium since the efficacy of probiotics often relies on the number of viable cells at the time of consumption. Stabilization of cells is required since these products are normally stored under challenging conditions in animal farm i.e. high relative humidity, high temperature and constantly exposed to air. The objective of this research is to develop a low cost and cell-friendly technique for encapsulating probiotic cells for animal use. The cells would be first entrapped in ca-alginate hydrogel beads and subsequently coated with polycations such as chitosan. The encapsulated probiotics cells will then be dried and the storage stability of cells will be monitored under conditions mimicking the hot and humid weather in Malaysia.   

LEE BOON BENG

Bioencapsulation for high density cultivation of cells.

 Liquid-core capsules have been used for cultivation of high cell density. Cell suspension is encapsulated and confined within a semi permeable polymeric membrane, which retain the cells but allow nutrients and by-products to pass through it. Alginate is the most commonly used material for making the semi permeable membrane.  However, the problems with alginate are that the gels formed are chemically unstable and mechanically weak. In this research, к-carrageenan which can be extracted from local seaweeds, is proposed as an alternative encapsulation material because it can form strong and chemically stable gels. The overall objective of this research is to devise a method to produce к-carrageenan membrane capsules containing live cells for developing high cell density cultivation system.

WONG SZE LING

Preparation of probiotic-starch granules as potential functional food

The current food industry is directing towards the development of functional foods due to their perceived image in promoting better health. The objective of this research is to devise a method for preparation of probiotic-starch as potential functional food. The reasons are to find new application for these crops and to add-value to their current raw product. The present research is aimed at finding ways to bind the cells and starch granules together and to produce a favorable taste and texture from fermentation. The starches used in this study are derived from local crops such as sago, tapioca and sweet potato. The product of this study is expected to increase demand for these crops and therefore improve the quality of life of crop farmers.

CHEN SEW WEE

The rheological properties of polymer solution in bioencapsulation.

Bioencapsulation is a process of making capsules or beads for applications in bioprocess, medicine, drugs delivery, food,  bioremediation etc. These hydrogel particles can be made from various polymeric materials such as alginate, pectin, k-carraageenan, xanthan gum, starch. It has been shown that the rheological properties such as viscosity have significant influence on the physical characteristics of the particles formed. The aim of this research is to study the rheological properties of these polymer materials. Among the variables under investigation are such as agitation, concentration and temperature.

HO KUET CHONG

Biodiesel from Biomass

Biodiesel is an alternative diesel fuel, which is made from renewable biological sources such as vegetable oils and animal fats. It is environmentally beneficial because of biodegradable, nontoxic and low emission profiles and has become more attractive recently because of the increases in crude oil prices, limited resources of fossil oil and environmental concerns of traditional fuel. The objective of this research is to convert palm oil through transesterification process to produce biodiesel. The relationship of molar ratio of oils to alcohol, the effects of catalysts, reaction temperature, reaction time and free fatty acids and water content of oils or fats will be studied to obtain the highest conversion.

HONG WAI ONN

Production of capsules using co-extrusion technique.

Encapsulation is the process by which a gaseous, liquid or solid encapsulant, is surrounded by a continuous film or coating. Consequently, the core of the capsules contains the encapsulant, which is prevented from contact with the surroundings by the capsule membrane. The advantages of encapsulation in bioprocess applications are such as (i) continuous operation of the system at high dilution rates, with no danger of the cells being washed out (ii) fast reaction rates at high density (iii) high yield of the product and easy to scale up, (iv) provide protection from shear forces prevailing in a bioreactor and (vi) avoid from contamination during storage and dosage tool for starter cultures.  In this research, liquid core capsules will be produced by using co-extrusion technique. The influence of alginate to liquid-core flow rates and viscosity of solutions on capsules properties (size of the capsules, size distribution and membrane thickness of the capsules) will be investigated.

JAMIL LUDIN

Single Cell Protein Production from Pineapple Skin by Aspergillus Niger.

Single cell protein (SCP) is defined as the protein extracted from cultivated microbial biomass and used as a protein sources in human foods and domestic animals feeds. In Sabah, there are many sectors utilize local fruits such as pineapple, banana and sugarcane as a raw material to produce different type of drinking and food product. In this project, pineapple skin will be utilized as substrate. Aspergillus niger will be used to convert the substrate to single cell protein. The fermentation process will be accomplished by using batch reactor system. The effect of substrate concentration on cell growth will be studied.

JOREEN LIM

Mass transport properties of hydrogel beads/capsules

Alginates gel is widely used for immobilization of biological materials since its gel particles can be prepared by simple techniques under mild conditions. However it is widely known that alginate gels lack chemical and mechanical stability. It has been suggested that ca-pectinate hydrogels could be a better alternative. In the case of encapsulation of biological materials, the permeability of the hydrogel must not restrict the inflow of nutrients and outflow of metabolites. The overall objective of this research is to evaluate the suitability of ca-pectinate hydrogels for use in bioprocesses by studying the mass transport properties of ca-pectinate hydrogel. The data will then be compared to that of ca-alginate hydrogels.

KIM SHIH YUEN

Single cell protein (SCP) from banana skins (agrowaste) reclamation.

Single-cell protein (SCP) refers to the dried cells of microorganisms. SCPs are used as protein sources in human foods or animal feeds. The objectives of this are to study the parameters that affect the production of SCP and to develop the optimum conditions. Many raw materials have been studied as substrates for the production of SCP. In this project, the agrowaste, banana skins will be used as the substrate. Also, Aspergillus oryzae will be used as the culture. Here, the parameters will be studied are temperature, inoculum size and quantity of substrate that using for the fermentation.

LEE KEAN HENG

Effect of hygroscopicity of additives on storage stability of dehydrated probiotic cells. 

Storage stability of cells is generally affected by environmental factors such as temperatures, humidity and presence of air. In the past, many polymeric additives have been used to improve storage stability of probiotic cells. However, in most cases, the use of these materials was based on trial and error method. Since it has been found that the water activity of dehydrated cell culture has great influence on storage stability, the objective of this research is to find out if there is a relationship between the hygroscopicity of polymeric additives and storage stability of cells. This can be investigated by studying the water uptake kinetics of additives.

LEE PEH PHONG

Factors affecting survival of probiotic cells during exposure to simulated gastric fluid.

  Acid tolerance of probiotic cells has been viewed as one of the main criteria for strain selection. Acid tolerance of many strains has been evaluated by many workers and current perspective is that it is strain-dependent and pH-dependent. However, direct comparison of cell survival might be misleading since the materials and methods used among researchers were not consistent. This study aims to evaluate the effect of materials and methods on acid tolerance of selected probiotic cells. The outcome of this work can be used to propose a standard materials and method for evaluation of acid tolerance of probiotic cells.  

LEE YEE CHING

Measurement of glucose concentration in biological medium using enzymatic glucose kit.

Glucose has been widely used as substrate in many fermentation processes because it is the simplest form of carbon source for microorganisms. Monitoring of glucose concentration is always essential in a bioprocess since it reflects the metabolic activity of cells. The common glucose analyses are based on enzymatic, chromatography, and amperometric methods. However, these methods are expensive and their operations require competent technical skills. In this project, I propose to use a diabetes kit to measure glucose concentration in fermentation medium. The first part of the research will focus on determining the accuracy and repeatability of the kit. Since fermentation medium often comprises of many other compounds, second part of this research is to investigate the effect of certain cell metabolites as well as pH on glucose measurement  

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LEONG JUN YEE

Production of beads/capsules using jet-cutting technique.

The aim of this research is to develop a method for large-scale production and uniform hydrogel beads/capsules. We proposed to use jet-cutting method since it has been shown that it can produce monodisperse beads at high production rate. Experiments will be performed to investigate the effect of process parameters (fluid flow rate, cutting speed, cutting angle, filaments diameter and nozzle diameter) on the size distribution and cutting loss of beads. The experimental data will then be compared to the theoretical model. 

LEONG TING SAIN

Enzymatic hydrolysis of local crops.

Local crops like tapioca, corn, and sago are easily available in Malaysia can be used to produce starch. Starch granules consist of two major type of glucose polymer, which are amylose and amylopectin. The overall objective is to produce glucose by enzymatic hydrolysis of commercial starch. I would like to determine the effect of starch to enzymes concentrations, and reaction duration on hydrolysis of commercial starch. A model to describe the hydrolysis reaction will be established.

LIM TING SUAN

Effect of porosity on adhesion of probiotic cells to starch granules.

In this research, I propose to study the relationship between the porosity and binding capacity of Lactobacillus species to starch granules. Since it was found by Crittenden et al. (2001) that surface area and binding capacity is directly related, hydrolysis of starch to create more porous starch structure is believed to yield more surface area and therefore increase the degree of cells adhesion. In the study, the granules will be hydrolyzed by using enzymatic reagent with non-gelatinization temperature. The starches of interest are derived from local crops such as tapioca, sago and sweet potato.

LOW POW EE

Production of microbeads using air-atomization technique for microencapsulation of probiotic cells.

In the recent years, probiotic cells have been used as substitute of antibiotics in poultry industry for the production of organic chickens. However, the short shelf life of probiotic cells remains as a problem to manufacturers as well as farmers, as it might affect the efficacy of the product.  The overall objective of this study is to develop a cost effective bioencapsulation method based on air-atomisation technique for microencapsulation of probiotic cells. First stage of this study focuses on finding out relationships between process variables (air flow rate, air pressure, liquid flow rate, concentration of sodium alginate and distance between air-atomisation nozzle and surface of calcium chloride bath) on microbeads properties. This knowledge will be subsequently applied for microencapsulation of probiotic cells. The final stage is to evaluate the stability of encapsulated probiotic cells during storage.  

NEO PEI YIN

Technological stress challenge on probiotic cells.

Recent advances in probiotic research have confirmed the health benefits of some probiotic bacterial strains. Nowadays, the application of probiotics is no longer restricted to human foods but also to animal livestock. Manufacture of probiotics involves many processing steps. Maintaining the viability of cells during processing and storage has been a challenge or problem to manufacturers, as the efficacy of a probiotic products is directly dependent on the availability of a preparation. The objective of this research is to study the response of probiotic cells when subjected to processing stresses. The relationships among the stresses and cell response will be established and the outcome can be used for selection of technological stress-resistance probiotic cells.     

ONG PEK SAN

Growth kinetic of commercial lactic acid bacteria

Nowadays, the applications of lactic acid bacteria (LAB) encompass many areas such as food, cosmetics, healthcare products, medicine, pharmaceutical, and etc. Fermentation of LAB is a product inhibition process and its growth kinetics normally follows the Monod and Leudeking-Piret model. In this research project, I propose to study the growth kinetic of Lactobacillus casei 01 which is of commercial importance. The first stage of this research is to determine the growth kinetics parameters such as µ_max (maximum growth rate), K_s(saturation constant), and K_p(product inhibition constant). This is followed by development of kinetic model for the cells. Finally, the kinetic model will be validated through experimental data.

THOMAS THUM

Formulation for stabilization of freeze-dried probiotic culture.

It has been found that the dehydrated powders containing probiotic cells often exhibit hygroscopic properties. When the powders are stored under challenging conditions (high RH, presence of air), it will result in great loss of cell survival as well as making the powders sticky. These problems could undoubtly limit the application of probiotics. This research project is aimed to address two problems: preserving the viability of cells and improving the flowability of powders containing cells during storage. It is proposed to study the effects of food grade silica, ascorbic acid and food-grade talc on cell stability and powders flowability when stored under conditions mimicking the hot and humid weather in Malaysia.   

WAN SIEW WAH

High density cultivation of bacterial cells using perfusion system.

Perfusion cultivation of microorganism is an efficient technique in the production of biomass and extra cellular metabolites. Perfusion cultivation system physically retains the cells within the vessel by withdrawing the spent medium while replenishing it with fresh medium simultaneously. The objective of this research is to develop a perfusion system for bacterial cells by using a specially designed cylindrical baffle. This will create a stagnant zone outside baffle to allow for settling of bacterial cells. In this way, spent medium can be continuously withdrawn within this zone and fresh medium can be continuously supplied in the mixing zone inside the baffle. The relationships of baffle configuration, agitation speed and cell size on separation efficiency of spent medium will be established.