Kinetics of Kojic Acid Fermentation by Aspergillus flavus Link S44-1 Using Sucrose as a Carbon Source under Different pH Conditions

Rosfarizan M.,Ariff A.B. The Korean Society for Biotechnology and Bioengine 2006 Biotechnology and Bioprocess Engineering Vol.11 No.1

Kojic acid production by Aspergillus flavus strain S44-1 using sucrose as a carbon source was carried out in a 250-mL shake flask and a 2-L stirred tank fermenter. For comparison, production of kojic acid using glucose, fructose and its mixture was also carried out. Kojic acid production in shake flask fermentation was 25.8 g/L using glucose as the sole carbon source, 23.6 g/L with sucrose, and 6.4 g/L from fructose. Reduced kojic acid production (13.5 g/L) was observed when a combination of glucose and fructose was used as a carbon source. The highest production of kojic acid (40.2 g/L) was obtained from 150 g/L sucrose in a 2 L fermenter, while the lowest kojic acid production (10.3 g/L) was seen in fermentation using fructose as the sole carbon source. The experimental data from batch fermentation and resuspended cell system was analysed in order to form the basis for a kinetic model of the process. An unstructured model based on logistic and Luedeking-Piret equations was found suitable to describe the growth, substrate consumption, and efficiency of kojic acid production by A. flavus in batch fermentation using sucrose. From this model, it was found that kojic acid production by A. flavus was not a growth-associated process. Fermentation without pH control (from an initial culture pH of 3.0) showed higher kojic acid production than single-phase pH-controlled fermentation (pH 2.5, 2.75, and 3.0).

Kinetics of Kojic Acid Fermentation by Aspergillus flavus Link S44-1 Using Sucrose as a Carbon Source under Different pH Conditions

M. Rosfarizan,A. B. Ariff 한국생물공학회 2006 Biotechnology and Bioprocess Engineering Vol.11 No.1

Kojic acid production by Aspergillus flavus strain S44-1 using sucrose as a carbon source was carried out in a 250-mL shake flask and a 2-L stirred tank fermenter. For comparison, production of kojic acid using glucose, fructose and its mixture was also carried out. Kojic acid production in shake flask fermentation was 25.8 g/L using glucose as the sole carbon source, 23.6 g/L with sucrose, and 6.4 g/L from fructose. Reduced kojic acid production (13.5 g/L) was observed when a combination of glucose and fructose was used as a carbon source. The highest production of kojic acid (40.2 g/L) was obtained from 150 g/L sucrose in a 2 L fermenter, while the lowest kojic acid production (10.3 g/L) was seen in fermentation using fructose as the sole carbon source. The experimental data from batch fermentation and resuspended cell system was analysed in order to form the basis for a kinetic model of the process. An unstructured model based on logistic and Luedeking-Piret equations was found suitable to describe the growth, substrate consumption, and efficiency of kojic acid production by A. flavus in batch fermentation using sucrose. From this model, it was found that kojic acid production by A. flavus was not a growth-associated process. Fermentation without pH control (from an initial culture pH of 3.0) showed higher kojic acid production than single-phase pH-controlled fermentation (pH 2.5, 2.75, and 3.0).

Improved Production of Live Cells of Lactobacillus rhamnosus by Continuous Cultivation using Glucose-yeast Extract Medium

Liew Siew Ling,Rosfarizan Mohamad,Raha Abdul Rahim,Arbakariya Bin Ariff,Ho Yin Wan 한국미생물학회 2006 The journal of microbiology Vol.44 No.4

In this study, the growth kinetics of Lactobacillus rhamnosus and lactic acid production in continuous culture were assessed at a range of dilution rates (0.05 h–1 to 0.40 h–1) using a 2 L stirred tank fermenter with a working volume of 600 ml. Unstructured models, predicated on the Monod and Luedeking-Piret equations, were employed to simulate the growth of the bacterium, glucose consumption, and lactic acid production at different dilution rates in continuous cultures. The maximum specific growth rate of L. rhamnosus, μmax, was estimated at 0.40 h–1, and the Monod cell growth saturation constant, Ks, at approximately 0.25 g/L. Maximum cell viability (1.3 × 1010 CFU/ml) was achieved in the dilution rate range of D = 0.28 h–1 to 0.35 h–1. Both maximum viable cell yield and productivity were achieved at D = 0.35 h–1. The continuous cultivation of L. rhamnosus at D = 0.35 h–1 resulted in substantial improvements in cell productivity, of 267% (viable cell count) that achieved via batch cultivation.

Improved Production of Live Cells of Lactobacillus rhamnosus by Continuous Cultivation using Glucose-yeast Extract Medium

Ling Liew Siew,Mohamad Rosfarizan,Rahim Raha Abdul,Wan Ho Yin,Ariff Arbakariya Bin The Microbiological Society of Korea 2006 The journal of microbiology Vol.44 No.4

In this study, the growth kinetics of Lactobacillus rhamnosus and lactic acid production in continuous culture were assessed at a range of dilution rates $(0.05 h^{-1}\;to\;0.40h^{-1})$ using a 2L stirred tank fermenter with a working volume of 600ml. Unstructured models, predicated on the Monod and Luedeking-Piret equations, were employed to simulate the growth of the bacterium, glucose consumption, and lactic acid production at different dilution rates in continuous cultures. The maximum specific growth rate of L. rhamnosus, ${\mu}_{max}$, was estimated at $0.40h^{-1}$I, and the Monod cell growth saturation constant, Ks, at approximately 0.25g/L. Maximum cell viability $(1.3{\times}10^{10}CFU/ml)$ was achieved in the dilution rate range of $D=0.28h^{-1}\;to\;0.35h^{-1}$. Both maximum viable cell yield and productivity were achieved at $D=0.35h^{-1}$. The continuous cultivation of L. rhamnosus at $D=0.35h^{-1}$ resulted in substantial improvements in cell productivity, of 267% (viable cell count) that achieved via batch cultivation.

Improvements of GC and HPLC Analyses in Solvent (Acetone-Butanol-Ethanol) Fermentation by Clostridium saccharobutylicum Using a Mixture of Starch and Glycerol as Carbon Source

Arbakariya Bin Ariff,Liew Shiau Tsuey,Rosfarizan Mohamad,Raha Abdul Rahim 한국생물공학회 2006 Biotechnology and Bioprocess Engineering Vol.11 No.4

A study on the feasibility of using improved computer-controlled HPLC and GC systems was carried out to shorten the time needed for measuring levels of the substrates (glucose, maltose, and glycerol) and products (acetone, butanol ethanol, acetic acid, and butyric acid) produced by Clostridium saccharobutylicum DSM 13864 during direct fermentation of sago starch to solvent. The use of HPLC system with a single injection to analyse the composition of culture broth (substrates and products) during solvent fermentation was achieved by raising the column temperature to 80oC. Although good separation of the components in the mixture was achieved, a slight overlap was observed in the peaks for butyric acid and acetone. The shape of the peak obtained and the analysis time of 26.66 min were satisfactory at a fixed flow rate of 0.8 mL/min. An improved GC system was developed, that was able to measure the products of solvent fermentation (acetone, butanol, ethanol, acetic acid, and butyric acid) within 19.28 min. Excellent resolution for each peak was achieved by adjusting the oven temperature to 65oC.

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%.

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.

Improvements of GC and HPLC Analyses in Solvent (Acetone-Butanol-Ethanol) Fermentation by Clostridium saccharobutylicum Using a Mixture of Starch and Glycerol as Carbon Source

Tsuey, Liew Shiau,Ariff, Arbakariya Bin,Mohamad, Rosfarizan,Rahim, Raha Abdul The Korean Society for Biotechnology and Bioengine 2006 Biotechnology and Bioprocess Engineering Vol.11 No.4

A study on the feasibility of using improved computer-controlled HPLC and GC systems was carried out to shorten the time needed for measuring levels of the substrates (glucose, maltose, and glycerol) and products (acetone, butanol ethanol, acetic acid, and butyric acid) produced by Clostridium saccharobutylicum DSM 13864 during direct fermentation of sago starch to solvent. The use of HPLC system with a single injection to analyse the composition of culture broth (substrates and products) during solvent fermentation was achieved by raising the column temperature to $80^{\circ}C$. Although good separation of the components in the mixture was achieved, a slight overlap was observed in the peaks for butyric acid and acetone. The shape of the peak obtained and the analysis time of 26.66 min were satisfactory at a fixed flow rate of 0.8mL/min. An improved GC system was developed, that was able to measure the products of solvent fermentation (acetone, butanol, ethanol, acetic acid, and butyric acid) within 19.28 min. Excellent resolution for each peak was achieved by adjusting the oven temperature to $65^{\circ}C$.

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.

Effects of Enzyme Treated Palm Kernel Expeller on Metabolizable Energy, Growth Performance, Villus Height and Digesta Viscosity in Broiler Chickens

Saenphoom, P.,Liang, J.B.,Ho, Y.W.,Loh, T.C.,Rosfarizan, M. Asian Australasian Association of Animal Productio 2013 Animal Bioscience Vol.26 No.4

This study examined whether pre-treating palm kernel expeller (PKE) with exogenous enzyme would degrade its fiber content; thus improving its metabolizable energy (ME), growth performance, villus height and digesta viscosity in broiler chickens fed diets containing PKE. Our results showed that enzyme treatment decreased (p<0.05) hemicellulose and cellulose contents of PKE by 26.26 and 32.62%, respectively; and improved true ME (TME) and its nitrogen corrected value ($TME_n$) by 38% and 33%, respectively, compared to the raw sample. Average daily gain (ADG), feed intake and feed conversion ratio (FCR) of chickens fed on different dietary treatments in the grower period were not significantly different. Although there was no difference in feed intake (p>0.05) among treatment groups in the finisher period, ADG of chickens in the control (PKE-free diet) was higher (p<0.05) than in all treatment groups fed either 20 or 30% PKE, irrespective of with or without enzyme treatment. However, ADG of birds fed with 20% PKE was higher than those fed with 30% PKE. The FCR of chickens in the control was the lowest (2.20) but not significantly different from those fed 20% PKE diets while birds in the 30% PKE diets recorded higher (p>0.05) FCR. The intestinal villus height and crypt depth (duodenum, jejunum and ileum) were not different (p>0.05) among treatments except for duodenal crypt depth. The villus height and crypt depth of birds in enzyme treated PKE diets were higher (p<0.05) than those in the raw PKE groups. Viscosity of the intestinal digesta was not different (p>0.05) among treatments. Results of this study suggest that exogenous enzyme is effective in hydrolyzing the fiber (hemicellulose and cellulose) component and improved the ME values of PKE, however, the above positive effects were not reflected in the growth performance in broiler chickens fed the enzyme treated PKE compared to those received raw PKE. The results suggest that PKE can be included up to 5% in the grower diet and 20% in the finisher diet without any significant negative effect on FCR in broiler chickens.