Rahayu Ahmad | Universiti Sains Islam Malaysia (USIM) (original) (raw)

Papers by Rahayu Ahmad

Energies

The depletion of fossil fuels and the emission of greenhouse gases have increased the demand for ... more The depletion of fossil fuels and the emission of greenhouse gases have increased the demand for new and sustainable energy sources, leading to growing interest in using fast-growing filamentous fungi as a source of bioenergy. This study aimed to optimize the production of exopolysaccharides (EPS) and mycelial biomass (MB) from the native medicinal mushroom, Lignosus rhinocerus, through submerged liquid fermentation. Using response surface methodology (RSM), it was found that the glucose concentration and speed of agitation significantly influenced the production of MB and EPS (p < 0.05), while the initial pH medium had an insignificant effect. The validated optimized parameters of 50.0 g/L glucose, initial pH 4.0, and 128 rpm for speed of agitation were tested in 500 mL shake flasks, 5 L, and 13 L stirred-tank (STR) bioreactors. The production of MB and EPS increased significantly by ~1.2-fold in the 5 L STR and further increased to ~1.7-fold (MB) and ~2.4-fold (EPS) in the 13 L...

Biocatalysis and Agricultural Biotechnology, 2021

AIMS Agriculture and Food, 2018

In a commercial oyster mushroom farm, fruiting body base (FBB) was not harvested compared to the ... more In a commercial oyster mushroom farm, fruiting body base (FBB) was not harvested compared to the common cap and stem of the fruiting body parts, and thus remained as waste. In the present study, unused FBB was powdered and subjected to proximate analysis as floured FBB (FFBB). FFBB was found to contain 71.2% carbohydrate, 8.93% moisture, 7.18% fibre, 5.72% ash, 5.57% protein, and 1.4% fat, while raw-FBB (RFBB) contained 7.57% carbohydrate, 84.4% moisture, 5.17% fibre, 5.72% ash, 1.54% protein, and 0.85% fat. The high carbohydrate content of FFBB was subjected to hot-water extraction and yielded 7.40 g of FFBB polysaccharide (FFBBP). Total phenolic content (TPC) of FFBBP contained 1.80 mg gallic acid equivalents (GAE)/g, exhibiting the reducing activity of 1.74 mM Fe(II)/g by ferric reducing antioxidant power assay, and reduced the stable 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonate radical forms at IC50 of 25.08 mg/mL, which was comparable with other parts of oyster mushroom species. Different percentages of FFBB mixtures were utilized in the production of cookies (10% and 20%) and steamed buns (10%, 20% and 30%). Thirtyseven panellists were selected for sensory testing, which showed that 10% of FFBB in a steamed bun was more acceptable than 30% of FFBB, while the overall acceptance of cookies with 10% FBB was insignificant (p > 0.05) but 20% FFBB in cookies was significantly different from control (p < 0.05). This study indicates that potential value of FFBB as an economical antioxidative flour in the development of functional foods.

AIMS Microbiology, 2020

The pellet morphology and diameter range (DR) of Ganoderma lucidum were observed in a repeated-ba... more The pellet morphology and diameter range (DR) of Ganoderma lucidum were observed in a repeated-batch fermentation (RBF) for the trio total production of biomass, exopolysaccharide (EPS) and endopolysaccharide (ENS). Two factors were involved in RBF; broth replacement ratio (BRR: 60%, 75% and 90%) and broth replacement time point (BRTP: log, transition and stationary phase) in days. In RBF, 34.31 g/L of biomass favoured small-compact pellets with DR of 20.67 μm< d < 24.00 μm (75% BRR, day 11 of BRTP). EPS production of 4.34 g/L was prone to ovoid-starburst pellets with DR of 34.33 μm< d <35.67 μm (75% BRR, day 13 of BRTP). Meanwhile, the highest 2.43 g/L of ENS production favoured large-hollow pellets with DR of 34.00 μm< d < 38.67 μm (90% BRR, day 13 of BRTP). In addition, RBF successfully shortened the biomass-EPS-ENS fermentation period (31, 33 and 35 days) from batch to 5 days, in seven consecutive cycles of RBF. In a FTIR detection, β-AIMS Microbiology Volume 6, Issue 4, 379-400. glucan (BG) from EPS and ENS extracts were associated with β-glycosidic linkages (2925 cm-1 , 1635 cm-1 , 1077 cm-1 ,920 cm-1 and 800 cm-1 wavelengths) with similar 1 H NMR spectral behaviour (4.58, 3.87 and 3.81 ppm). Meanwhile, 4 mg/L of BG gave negative cytotoxic effects on normal gingival cell line (hGF) but induced antiproliferation (IC 50 = 0.23 mg/mL) against cancerous oral Asian cellosaurus cell line (ORL-48). Together, this study proved that G. lucidum mycelial pellets could withstand seven cycles of long fermentation condition and possessed anti-oral cancer beta-glucan, which suits large-scale natural drug fermentation.

Production of extracellular and intracellular polysaccharides (EPS, IPS) from Lentinus squarrosul... more Production of extracellular and intracellular polysaccharides (EPS, IPS) from Lentinus squarrosulus mycelium was carried out through submerged fermentation. The one-factor-at-a-time method was adopted to investigate the effect of medium components (carbon, nitrogen), and environmental factor (initial pH) on dry weight of mycelium and EPS concentration. Sucrose and yeast extract gave the highest EPS concentration with 3.56 mg/mL and 1.23 mg/mL respectively when carbon and nitrogen sources were employed. Combination of ammonium chloride and yeast extract (30:70) ratio increased the mycelium dry weight up to 10.8 g/L and EPS concentration of 4.39 mg/mL. An initial pH of 7.5 showed maximum EPS concentration of 3.82 mg/mL with mycelium dry weight of 7 g/L. Crude extracts from hot water and cold water extraction of Lentinus squarrosulus mycelium (IPS HWE, IPS CWE) and water extract from supernatant (EPS WE) was proved to have antiproliferative activity against A549 lung carcinoma cell lin...

Advances in Bioscience and Biotechnology, 2015

Advances in Bioscience and Biotechnology, 2014

Various crude extracts of Lentinus squarrosulus mushroom mycelium and culture broth were prepared... more Various crude extracts of Lentinus squarrosulus mushroom mycelium and culture broth were prepared for antioxidant studies, glucan and carbohydrate compound analysis. Crude extract from ethanol, cold and hot water extraction was tested on several complementary test systems namely DPPH free radical scavenging, β-carotene linoleic acid oxidation, total phenolic compound, total flavonoid compound, total carbohydrate content and total glucan compositions. The antioxidant activity of the crude extracts of Lentinus squarrosulus mushroom mycelium and culture broth was determined by 2,2' diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method and β-carotene linoleic acid assay. Crude extracted from culture broth EPS EE recorded the highest radical scavenging effects at 20 mg/mL (85%) which is closer to the control antioxidants (ascorbic acid 97%; BHT 92.4%; BHA 93.6%). Both the ethanol extract (IPS EE and EPS EE) exhibited the highest β-carotene linoleic acid oxidation by recording IC50 values of 0.6 and 0.65 mg/mL respectively. IPS EE (0.59 mg/g) and EPS WE (0.58 mg/g) showed high flavonoid content whereas total phenol content was high in EPS WE (0.85 mg/g) and IPS EE (0.84 mg/g). Total carbohydrate concentrations were high in IPS HWE and IPS CWE with 19.1 and 16.3 mg/mL respectively and these data correlate with the β-glucan content in both extracts. The highest β-glucan content found in IPS CWE and IPS HWE were 12.2 and 11.4% w/w respectively.

International Journal of Advanced Research, 2018

Mushroom is known to be a fungal growth which is in the form of filaments called as hyphae that c... more Mushroom is known to be a fungal growth which is in the form of filaments called as hyphae that can only be seen through microscope; with time, these hyphae grow into long network that are known as mycelium [1,2]. Mushrooms

AIMS Microbiology, 2019

Wild-cultivated medicinal mushroom Ganoderma lucidum was morphologically identified and sequenced... more Wild-cultivated medicinal mushroom Ganoderma lucidum was morphologically identified and sequenced using phylogenetic software. In submerged-liquid fermentation (SLF), biomass, exopolysaccharide (EPS) and intracellular polysaccharide (IPS) production of the identified G. lucidum was optimised based on initial pH, starting glucose concentration and agitation rate parameters using response surface methodology (RSM). Molecularly, the G. lucidum strain QRS 5120 generated 637 base pairs, which was commensurate with related Ganoderma species. In RSM, by applying central composite design (CCD), a polynomial model was fitted to the experimental data and was found to be significant in all parameters investigated. The strongest effect (p < 0.0001) was observed for initial pH for biomass, EPS and IPS production, while agitation showed a significant 20

Lecture Notes in Computer Science, 2011

Abstract. Blogs have democratized participation for everyone who wants to publish on the Internet... more Abstract. Blogs have democratized participation for everyone who wants to publish on the Internet. This trend, however, is problematic for readers trying to determine trustworthy and believeable sources. This blog diary study, allowed us to understand what aspects influenced ...

Innovations in Chemical Biology, 2009

A Gram negative bacterium, Cupriavidus sp. USMAA2-4 was isolated from a soil sample in Northern P... more A Gram negative bacterium, Cupriavidus sp. USMAA2-4 was isolated from a soil sample in Northern Peninsular of Malaysia and was able to synthesize polyhydroxyalkanoate containing 4-hydroxybutyrate unit when grown on γ γ γ γ-butyrolactone as the sole carbon source. The polyester was purified from freezedried cells and analyzed by nuclear magnetic resonance (NMR) spectroscopy. 1 H and 13 C NMR results confirmed the presence of 3HB and 4HB monomers. The isolated strain has the ability to synthesize poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] in a two step cultivation process on a medium containing γ γ γ γ-butyrolactone as the carbon source. A high fraction of 4HB monomer unit was obtained by manipulating the cell concentration, types of carbon sources and carbon source concentration in the cultivated medium. On the basis of the PHA composition, we suggest that carbon sources such as 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol and 1,12-dodecanediol resulted in a skewed PHA composition. On the other hand, the molar fraction of 4HB in P(3HB-co-4HB) was increased significantly from 25 -51 mol % by the higher concentration of γ γ γ γ-butyrolactone as the sole carbon source in the medium. The molecular weight and thermal properties of P(3HB-co-4HB) were revealed by gel permeation chromatography (GPC) and differential scanning calorimeter (DSC), respectively. We found that this bacterium is able to produce wide range copolymer with the numberaverage molecular weights (M n ) of copolymers ranging from 17 x 10 3 to 412 x 10 3 Dalton. Increase in the concentration of γ γ γ γ-butyrolactone lowered the molecular weight of these copolymers. Higher concentration of γ γ γ γ-butyrolactone also resulted in more branched polymer and consequently gave lower values for both the glass transition temperature (T g ) as well as melting temperature, T m .

Advances in Bioscience and Biotechnology, 2014

Advances in Bioscience and Biotechnology, 2013

The interaction between sucrose, yeast extract and initial pH was investigated to optimize critic... more The interaction between sucrose, yeast extract and initial pH was investigated to optimize critical medium components for mycelium biomass and production of exopolysaccharide (EPS) of Lentinus squarrosulus using Response Surface Methodology (RSM). A central composite design (CCD) was applied and a polynomial regression model with quadratic term was used to analyse the experimental data using analysis of variance (ANOVA). ANOVA analysis showed that the model was very significant (p < 0.0001) for both mycelium biomass and EPS production. The yeast extract concentrations and initial pH showed the strongest effect (p < 0.001) meanwhile sucrose concentrations showed significant value at p < 0.005 for mycelium biomass. For EPS production, only sucrose and yeast extract concentrations gave significant value with p < 0.001 and p < 0.005 respectively. The model was validated by applying the optimized conditions and 25.8 ± 0.9 g/L of mycelium biomass, and 5.7 ± 0.4 mg/mL EPS concentration was obtained. The estimated optimum conditions of the variables for the production of mycelium biomass and EPS production by Lentinus squarrosulus are as follows: sucrose concentration 114.61 g/L, yeast extract 1.62 g/L and initial pH of 5.81; sucrose concentration 115.8 g/L, yeast extract of 3.39 g/L and initial pH of 6.44 respectively.

Lecture Notes in Computer Science, 2011

Reliance on the Internet as a source of information has increased dramatically in recent years am... more Reliance on the Internet as a source of information has increased dramatically in recent years among information seekers. The reliability of information on the Internet can sometimes be questionable due to the absence of an editorial function. Users need to ...

Proceedings of the American Society for Information Science and Technology, 2010

Reliance on the Internet as a source of information has increased dramatically in recent years am... more Reliance on the Internet as a source of information has increased dramatically in recent years among information seekers. On the other hand, the advent of Web technologies has created unprecedented opportunity for information producers to easily publish information [4]. ...

Production of extracellular and intracellular polysaccharides (EPS, IPS) from Lentinus squarrosul... more Production of extracellular and intracellular polysaccharides (EPS, IPS) from Lentinus squarrosulus mycelium was carried out through submerged fermentation. The one-factor-at-a-time method was adopted to investigate the effect of medium components (carbon, nitrogen), and environmental factor (initial pH) on dry weight of mycelium and EPS concentration. Sucrose and yeast extract gave the highest EPS concentration with 3.56 mg/mL and 1.23 mg/mL respectively when carbon and nitrogen sources were employed. Combination of ammonium chloride and yeast extract (30:70) ratio increased the mycelium dry weight up to 10.8 g/L and EPS concentration of 4.39 mg/mL. An initial pH of 7.5 showed maximum EPS concentration of 3.82 mg/mL with mycelium dry weight of 7 g/L. Crude extracts from hot water and cold water extraction of Lentinus squarrosulus mycelium (IPS HWE, IPS CWE) and water extract from supernatant (EPS WE) was proved to have antiproliferative activity against A549 lung carcinoma cell lin...

Energies

The depletion of fossil fuels and the emission of greenhouse gases have increased the demand for ... more The depletion of fossil fuels and the emission of greenhouse gases have increased the demand for new and sustainable energy sources, leading to growing interest in using fast-growing filamentous fungi as a source of bioenergy. This study aimed to optimize the production of exopolysaccharides (EPS) and mycelial biomass (MB) from the native medicinal mushroom, Lignosus rhinocerus, through submerged liquid fermentation. Using response surface methodology (RSM), it was found that the glucose concentration and speed of agitation significantly influenced the production of MB and EPS (p < 0.05), while the initial pH medium had an insignificant effect. The validated optimized parameters of 50.0 g/L glucose, initial pH 4.0, and 128 rpm for speed of agitation were tested in 500 mL shake flasks, 5 L, and 13 L stirred-tank (STR) bioreactors. The production of MB and EPS increased significantly by ~1.2-fold in the 5 L STR and further increased to ~1.7-fold (MB) and ~2.4-fold (EPS) in the 13 L...

Biocatalysis and Agricultural Biotechnology, 2021

AIMS Agriculture and Food, 2018

In a commercial oyster mushroom farm, fruiting body base (FBB) was not harvested compared to the ... more In a commercial oyster mushroom farm, fruiting body base (FBB) was not harvested compared to the common cap and stem of the fruiting body parts, and thus remained as waste. In the present study, unused FBB was powdered and subjected to proximate analysis as floured FBB (FFBB). FFBB was found to contain 71.2% carbohydrate, 8.93% moisture, 7.18% fibre, 5.72% ash, 5.57% protein, and 1.4% fat, while raw-FBB (RFBB) contained 7.57% carbohydrate, 84.4% moisture, 5.17% fibre, 5.72% ash, 1.54% protein, and 0.85% fat. The high carbohydrate content of FFBB was subjected to hot-water extraction and yielded 7.40 g of FFBB polysaccharide (FFBBP). Total phenolic content (TPC) of FFBBP contained 1.80 mg gallic acid equivalents (GAE)/g, exhibiting the reducing activity of 1.74 mM Fe(II)/g by ferric reducing antioxidant power assay, and reduced the stable 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonate radical forms at IC50 of 25.08 mg/mL, which was comparable with other parts of oyster mushroom species. Different percentages of FFBB mixtures were utilized in the production of cookies (10% and 20%) and steamed buns (10%, 20% and 30%). Thirtyseven panellists were selected for sensory testing, which showed that 10% of FFBB in a steamed bun was more acceptable than 30% of FFBB, while the overall acceptance of cookies with 10% FBB was insignificant (p > 0.05) but 20% FFBB in cookies was significantly different from control (p < 0.05). This study indicates that potential value of FFBB as an economical antioxidative flour in the development of functional foods.

AIMS Microbiology, 2020

The pellet morphology and diameter range (DR) of Ganoderma lucidum were observed in a repeated-ba... more The pellet morphology and diameter range (DR) of Ganoderma lucidum were observed in a repeated-batch fermentation (RBF) for the trio total production of biomass, exopolysaccharide (EPS) and endopolysaccharide (ENS). Two factors were involved in RBF; broth replacement ratio (BRR: 60%, 75% and 90%) and broth replacement time point (BRTP: log, transition and stationary phase) in days. In RBF, 34.31 g/L of biomass favoured small-compact pellets with DR of 20.67 μm< d < 24.00 μm (75% BRR, day 11 of BRTP). EPS production of 4.34 g/L was prone to ovoid-starburst pellets with DR of 34.33 μm< d <35.67 μm (75% BRR, day 13 of BRTP). Meanwhile, the highest 2.43 g/L of ENS production favoured large-hollow pellets with DR of 34.00 μm< d < 38.67 μm (90% BRR, day 13 of BRTP). In addition, RBF successfully shortened the biomass-EPS-ENS fermentation period (31, 33 and 35 days) from batch to 5 days, in seven consecutive cycles of RBF. In a FTIR detection, β-AIMS Microbiology Volume 6, Issue 4, 379-400. glucan (BG) from EPS and ENS extracts were associated with β-glycosidic linkages (2925 cm-1 , 1635 cm-1 , 1077 cm-1 ,920 cm-1 and 800 cm-1 wavelengths) with similar 1 H NMR spectral behaviour (4.58, 3.87 and 3.81 ppm). Meanwhile, 4 mg/L of BG gave negative cytotoxic effects on normal gingival cell line (hGF) but induced antiproliferation (IC 50 = 0.23 mg/mL) against cancerous oral Asian cellosaurus cell line (ORL-48). Together, this study proved that G. lucidum mycelial pellets could withstand seven cycles of long fermentation condition and possessed anti-oral cancer beta-glucan, which suits large-scale natural drug fermentation.

Production of extracellular and intracellular polysaccharides (EPS, IPS) from Lentinus squarrosul... more Production of extracellular and intracellular polysaccharides (EPS, IPS) from Lentinus squarrosulus mycelium was carried out through submerged fermentation. The one-factor-at-a-time method was adopted to investigate the effect of medium components (carbon, nitrogen), and environmental factor (initial pH) on dry weight of mycelium and EPS concentration. Sucrose and yeast extract gave the highest EPS concentration with 3.56 mg/mL and 1.23 mg/mL respectively when carbon and nitrogen sources were employed. Combination of ammonium chloride and yeast extract (30:70) ratio increased the mycelium dry weight up to 10.8 g/L and EPS concentration of 4.39 mg/mL. An initial pH of 7.5 showed maximum EPS concentration of 3.82 mg/mL with mycelium dry weight of 7 g/L. Crude extracts from hot water and cold water extraction of Lentinus squarrosulus mycelium (IPS HWE, IPS CWE) and water extract from supernatant (EPS WE) was proved to have antiproliferative activity against A549 lung carcinoma cell lin...

Advances in Bioscience and Biotechnology, 2015

Advances in Bioscience and Biotechnology, 2014

Various crude extracts of Lentinus squarrosulus mushroom mycelium and culture broth were prepared... more Various crude extracts of Lentinus squarrosulus mushroom mycelium and culture broth were prepared for antioxidant studies, glucan and carbohydrate compound analysis. Crude extract from ethanol, cold and hot water extraction was tested on several complementary test systems namely DPPH free radical scavenging, β-carotene linoleic acid oxidation, total phenolic compound, total flavonoid compound, total carbohydrate content and total glucan compositions. The antioxidant activity of the crude extracts of Lentinus squarrosulus mushroom mycelium and culture broth was determined by 2,2' diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method and β-carotene linoleic acid assay. Crude extracted from culture broth EPS EE recorded the highest radical scavenging effects at 20 mg/mL (85%) which is closer to the control antioxidants (ascorbic acid 97%; BHT 92.4%; BHA 93.6%). Both the ethanol extract (IPS EE and EPS EE) exhibited the highest β-carotene linoleic acid oxidation by recording IC50 values of 0.6 and 0.65 mg/mL respectively. IPS EE (0.59 mg/g) and EPS WE (0.58 mg/g) showed high flavonoid content whereas total phenol content was high in EPS WE (0.85 mg/g) and IPS EE (0.84 mg/g). Total carbohydrate concentrations were high in IPS HWE and IPS CWE with 19.1 and 16.3 mg/mL respectively and these data correlate with the β-glucan content in both extracts. The highest β-glucan content found in IPS CWE and IPS HWE were 12.2 and 11.4% w/w respectively.

International Journal of Advanced Research, 2018

Mushroom is known to be a fungal growth which is in the form of filaments called as hyphae that c... more Mushroom is known to be a fungal growth which is in the form of filaments called as hyphae that can only be seen through microscope; with time, these hyphae grow into long network that are known as mycelium [1,2]. Mushrooms

AIMS Microbiology, 2019

Wild-cultivated medicinal mushroom Ganoderma lucidum was morphologically identified and sequenced... more Wild-cultivated medicinal mushroom Ganoderma lucidum was morphologically identified and sequenced using phylogenetic software. In submerged-liquid fermentation (SLF), biomass, exopolysaccharide (EPS) and intracellular polysaccharide (IPS) production of the identified G. lucidum was optimised based on initial pH, starting glucose concentration and agitation rate parameters using response surface methodology (RSM). Molecularly, the G. lucidum strain QRS 5120 generated 637 base pairs, which was commensurate with related Ganoderma species. In RSM, by applying central composite design (CCD), a polynomial model was fitted to the experimental data and was found to be significant in all parameters investigated. The strongest effect (p < 0.0001) was observed for initial pH for biomass, EPS and IPS production, while agitation showed a significant 20

Lecture Notes in Computer Science, 2011

Abstract. Blogs have democratized participation for everyone who wants to publish on the Internet... more Abstract. Blogs have democratized participation for everyone who wants to publish on the Internet. This trend, however, is problematic for readers trying to determine trustworthy and believeable sources. This blog diary study, allowed us to understand what aspects influenced ...

Innovations in Chemical Biology, 2009

A Gram negative bacterium, Cupriavidus sp. USMAA2-4 was isolated from a soil sample in Northern P... more A Gram negative bacterium, Cupriavidus sp. USMAA2-4 was isolated from a soil sample in Northern Peninsular of Malaysia and was able to synthesize polyhydroxyalkanoate containing 4-hydroxybutyrate unit when grown on γ γ γ γ-butyrolactone as the sole carbon source. The polyester was purified from freezedried cells and analyzed by nuclear magnetic resonance (NMR) spectroscopy. 1 H and 13 C NMR results confirmed the presence of 3HB and 4HB monomers. The isolated strain has the ability to synthesize poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] in a two step cultivation process on a medium containing γ γ γ γ-butyrolactone as the carbon source. A high fraction of 4HB monomer unit was obtained by manipulating the cell concentration, types of carbon sources and carbon source concentration in the cultivated medium. On the basis of the PHA composition, we suggest that carbon sources such as 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol and 1,12-dodecanediol resulted in a skewed PHA composition. On the other hand, the molar fraction of 4HB in P(3HB-co-4HB) was increased significantly from 25 -51 mol % by the higher concentration of γ γ γ γ-butyrolactone as the sole carbon source in the medium. The molecular weight and thermal properties of P(3HB-co-4HB) were revealed by gel permeation chromatography (GPC) and differential scanning calorimeter (DSC), respectively. We found that this bacterium is able to produce wide range copolymer with the numberaverage molecular weights (M n ) of copolymers ranging from 17 x 10 3 to 412 x 10 3 Dalton. Increase in the concentration of γ γ γ γ-butyrolactone lowered the molecular weight of these copolymers. Higher concentration of γ γ γ γ-butyrolactone also resulted in more branched polymer and consequently gave lower values for both the glass transition temperature (T g ) as well as melting temperature, T m .

Advances in Bioscience and Biotechnology, 2014

Advances in Bioscience and Biotechnology, 2013

The interaction between sucrose, yeast extract and initial pH was investigated to optimize critic... more The interaction between sucrose, yeast extract and initial pH was investigated to optimize critical medium components for mycelium biomass and production of exopolysaccharide (EPS) of Lentinus squarrosulus using Response Surface Methodology (RSM). A central composite design (CCD) was applied and a polynomial regression model with quadratic term was used to analyse the experimental data using analysis of variance (ANOVA). ANOVA analysis showed that the model was very significant (p < 0.0001) for both mycelium biomass and EPS production. The yeast extract concentrations and initial pH showed the strongest effect (p < 0.001) meanwhile sucrose concentrations showed significant value at p < 0.005 for mycelium biomass. For EPS production, only sucrose and yeast extract concentrations gave significant value with p < 0.001 and p < 0.005 respectively. The model was validated by applying the optimized conditions and 25.8 ± 0.9 g/L of mycelium biomass, and 5.7 ± 0.4 mg/mL EPS concentration was obtained. The estimated optimum conditions of the variables for the production of mycelium biomass and EPS production by Lentinus squarrosulus are as follows: sucrose concentration 114.61 g/L, yeast extract 1.62 g/L and initial pH of 5.81; sucrose concentration 115.8 g/L, yeast extract of 3.39 g/L and initial pH of 6.44 respectively.

Lecture Notes in Computer Science, 2011

Reliance on the Internet as a source of information has increased dramatically in recent years am... more Reliance on the Internet as a source of information has increased dramatically in recent years among information seekers. The reliability of information on the Internet can sometimes be questionable due to the absence of an editorial function. Users need to ...

Proceedings of the American Society for Information Science and Technology, 2010

Reliance on the Internet as a source of information has increased dramatically in recent years am... more Reliance on the Internet as a source of information has increased dramatically in recent years among information seekers. On the other hand, the advent of Web technologies has created unprecedented opportunity for information producers to easily publish information [4]. ...

Production of extracellular and intracellular polysaccharides (EPS, IPS) from Lentinus squarrosul... more Production of extracellular and intracellular polysaccharides (EPS, IPS) from Lentinus squarrosulus mycelium was carried out through submerged fermentation. The one-factor-at-a-time method was adopted to investigate the effect of medium components (carbon, nitrogen), and environmental factor (initial pH) on dry weight of mycelium and EPS concentration. Sucrose and yeast extract gave the highest EPS concentration with 3.56 mg/mL and 1.23 mg/mL respectively when carbon and nitrogen sources were employed. Combination of ammonium chloride and yeast extract (30:70) ratio increased the mycelium dry weight up to 10.8 g/L and EPS concentration of 4.39 mg/mL. An initial pH of 7.5 showed maximum EPS concentration of 3.82 mg/mL with mycelium dry weight of 7 g/L. Crude extracts from hot water and cold water extraction of Lentinus squarrosulus mycelium (IPS HWE, IPS CWE) and water extract from supernatant (EPS WE) was proved to have antiproliferative activity against A549 lung carcinoma cell lin...