Heri Hermansyah

Enhancement of carbon dioxide fixation by alteration of illumination duringChlorella vulgaris-Buitenzorg's growth

Alteration of illumination with optimum carbon dioxide fixation-based curve in this research successfully enhanced the CO2-fixation (qco2) capability ofChlorella vulgaris Buitenzorg cultivated in a bubble column photo bioreactor. The level of CO2 fixation was up to 1.91 times that observed from cultivation with intensification of illumination on an optimum growth-based curve. During 144 h of cultivation, alteration of light intensity on an optimum CO2-fixation-based curve produced a qCO2 of 6.68 h−1. Increases in light intensity based on a curve of optimum CO2-fixation produced a final cell concentration of about 5.78 g/L. Both cultivation methods were carried out under ambient pressure at a temperature of 29°C with a superficial gas velocity of 2.4 m/h (UG). Cells were grown on Beneck medium in a 1.0 L Bubble Column Photo bioreactor illuminated by aPhillips Halogen Lamp (20 W/12 V/50 Hz). The inlet gas had a carbon dioxide content of 10%.

Rigorous kinetic model considering positional specificity of lipase for enzymatic stepwise hydrolysis of triolein in biphasic oil-water system

A rigorous kinetic model describing the stepwise triglyceride hydrolysis at the oil–water interface, based on the Ping Pong Bi Bi mechanism using suspended lipase having positional specificity, was constructed. The preference of the enzyme to cleave to the ester bonds at the edge and the center of the glycerol backbone of the substrates (tri-, di- or monoglyceride) was incorporated in the model. This model was applied to the experimental results for triolein hydrolysis using suspended Porcine pancreatic lipase (an sn-1,3 specific lipase) and Candida rugosa lipase (a non-specific lipase) in a biphasic oil–water system under various operating conditions. In order to discuss the model’s advantages, other models that do not consider the positional specificity of the lipase were also applied to our experimental results. The model considering the positional specificity of the lipase gave results which fit better with the experimental data and described the effect of the initial enzyme concentration, the interfacial area, and the initial concentrations of triolein on the entire process of the stepwise triolein hydrolysis. This model also gives a good representation of the rate for cleaving the respective ester bonds of each substrate by each type of lipase.

Preparation of the Edible Biocomposite Film Gelatin/Bacterial Cellulose Microcrystal (BCMC): Variation of Matrix Concentration, Filler, and Sonication Time

Several biodegradable polymers have been explored to develop biodegradable edible films in order to reduce the use of conventional plastics. In this study, edible biocomposite film is made from gelatin filled with Bacterial Cellulose Microcrystal (BCMC). BCMC is produced from nata de coco paste, which is hydrolyzed with cellulase enzyme. In making biocomposite, gelatin matrix is first dissolved in distilled water and then mixed with BCMC filler solution in ultrasonic bath. The solution resulted is then casted and dried in room temperature. The addition of BCMC is proven to improve physical properties, mechanical, and thermal properties of the resulting material. BCMC distribution of SEM showed increasing the tensile strength test results, DSC, and WVTR. When the BCMC concentration was varied from 1-4 wt% of the gelatin mass, tensile strength and glass transition temperature (Tg) increased from 37.07 MPa to 74.04 MPa and 27.520°C to 39.60°C, respectively. Water Vapour Transmission Rate (WVTR) decreased from 37.77 gr.m-2.h-1 to 19.73 gr.m-2.h-1. Tensile test and DSC results also increased when varying the sonication time from 3-6 minutes, from 48.57 MPa to 57.23 MPa and 25.890°C to 37.290°C. WVTR decreased from 36.09 gr.m-2.h-1 to 20.54 gr.m-2.h-1.

Solid State Fermentation using Agroindustrial Wastes to Produce Aspergillus Niger Lipase as a Biocatalyst Immobilized by an Adsorption-crosslinking Method for Biodiesel Synthesis

Although technological advances have fueled the rising demand for lipase as a biocatalyst, commercial availability remains limited and costs prohibitive. To meet this need, an extracellular lipase enzyme from Aspergillus niger can be produced through solid state fermentation (SSF) using agroindustrial wastes including tofu dregs, coconut dregs, and corn bran. These agroindustrial residues still contain nutrients, especially lipids/triglycerides, making them a potential fermentation medium to produce lipase. Lipase with the highest activity level (8.48 U/mL) was obtained using a tofu dreg substrate, 4% inducer concentration, and 9-day fermentation period. This crude lipase extract was then dried with a spray drier and immobilized in a macroporous anion resin using the adsorption-crosslinking method. The immobilized lipase’s activity was assayed by a biodiesel synthesis reaction; it showed 48.3% yield. The immobilized enzymes stability was also tested through four cycles of biodiesel synthesis; in the fourth cycle, the enzyme maintained 84% of its initial activity.

Production and characterization of cellulase from E. coli EgRK2 recombinant based oil palm empty fruit bunch

Oil Palm Empty Fruit Bunch (OPEFB) is an abundant biomass resource in Indonesia, which contains 41.3 ~ 46.5% (w/w) of cellulose. This research examined the production of cellulase by the E. coli EgRK2 recombinant strain using an OPEFB substrate. The production of the enzyme was initially examined to identify optimum growth conditions, by observing the growth and activity of E. coli EgRK2 compared to its wild type. Our results showed that the optimum production time, pH and temperature of the recombinant growth and cellulase activity were achieved at 24 h, and at 7 and 40°C, respectively. Using these optimum conditions, the enzyme was produced, and experiments were carried out to examine the enzyme characteristics, produced from both strains, on hydrolysis of cellulose from OPEFB. Our results showed that the activity of the enzyme produced by the recombinant almost doubled compared to that of the wild type, although the optimum pH for both strains was pH 6. Higher activity was achieved by the recombinant compared to the wild type strain, and values were 1.905 and 1.366 U/mL, respectively. The optimum temperature for hydrolysis by cellulase occurred at 50°C for Bacillus sp. RK2, and 60°C for Bacillus sp. EgRK2. The Michaelis-Menten constant (Km) and maximum velocity (Vmax) for OPEFB degradation by E. coli EgRK2 were 0.26% and 1.750 μmol/mL/sec, which were significantly better values than those of the wild type. Control experiments for the degradation test using CMC also showed a better Vmax value for E. coli EgRK2 compared to the wild type, which is 2.543 and 1.605 μmol/mL/sec, respectively.

Antiviral activity of Acanthaster planci phospholipase A2 against human immunodeficiency virus

Aim: Investigation of antiviral activity of Acanthaster planci phospholipase A2 (AP-PLA2) from moluccas to human immunodeficiency virus (HIV). Materials and Methods: Crude venom (CV) and F20 (PLA2 with 20% fractioned by ammonium sulfate) as a sample of PLA 2 obtained from A. planci’s extract were used. Enzymatic activity of PLA2 was determined using the degradation of phosphatidylcholine (PC). Activity test was performed using in vitro method using coculture of phytohemagglutinin-stimulated peripheral blood mononuclear cell (PBMC) from a blood donor and PBMC from HIV patient. Toxicity test of AP-PLA2 was done using lethal concentration required to kill 50% of the population (LC50). Results: AP-PLA2 F20 had activity and purity by 15.66 times bigger than CV. The test showed that the LC50 of AP-PLA2 is 1.638 mg/ml. Antiviral analysis of AP-PLA2 in vitro showed the inhibition of HIV infection to PBMC. HIV culture with AP-PLA2 and without AP-PLA2 has shown the number of infected PBMC (0.299±0.212% and 9.718±0.802%). Subsequently, RNA amplification of HIV using reverse transcriptase-polymerase chain reaction resulted in the decrease of band intensity in gag gene of HIV. Conclusion: This research suggests that AP-PLA2 has the potential to develop as an antiviral agent because in vitro experiment showed its ability to decrease HIV infection in PBMC and the number of HIV ribonucleic acid in culture.

Tapioca and tofu waste utilization to produce AA, DHA, and EPA

Human body has limited ability to synthesize unsaturated fatty acids such as AA, DHA, EPA. These fatty acids are essential for the body. This study initiated the efforts to produce unsaturated fatty acids of microorganisms, with low cost and high percentage. This study used tapioca and tofu waste as a medium for Aspergillus. In addition, this study analyzed the varying of carbon concentration to the maximum lipid production from Aspergillus oryzae and determine the optimum rate of agitation against lipid production from Aspergillus oryzae. The results shows that the optimum composition of AA, DHA, EPA are 0.18% (w / w), 0.33% (w / w), and 2.96% (w/w) respectively in concentration carbon of 9% (w/w) and agitation rate of 120 RPM.

Lipase production from Bacillus subtilis with submerged fermentation using waste cooking oil

Bacterial lipase has been developed lately because of its advantage to produce with large scale. Culture of Bacillus subtilis was grown to produce lipase in Waste Cooking Oil (WCO) using submerged fermentation (SmF) method. The enzyme activity of the culture was improved by using different concentration of inoculum, substrate, nitrogen source, inducer, and Ca2+ ion at 30°C for 84h fermentation. Lipolytic activity of crude lipase was determined using titrimetric method with hydrolysis reaction. Maximum activity of lipase (4.96 U/mL) was found at 5% (v/v) inoculum, 4% (v/v) WCO, 0.5% (w/v) yeast extract, 0.25% (v/v) olive oil, and 10 mM Ca2+ that present in medium culture. Later, the crude lipase has been dried with spray dryer and resulting 17.33 gr of dry lipase powder per 500 mL crude lipase.

Use of Nicotiana tabacum L extract for anti-Aedes Aegypti mosquito paint

This study intended to formulate mosquito repellent paints based tobacco leaf extracts-free pyrethroid substance which is safe for users. The active substance which was added to the paint as a mosquito repellent was an extract of tobacco leaves. The result of Anti-mosquito paint formulation produced was according to the Indonesia National Standard (SNI). The results of anti-Aedes Aegypti mosquito paint effectiveness test showed that 5% concentration of tobacco extract could kill half of the mosquito population (LC50) for 2 hours, the concentration of tobacco extract between 3-5% killed half the mosquito population (LC50) during 4 hours, while 1-3% and 0-1% concentration of tobacco extract killed half the mosquito population (LC50) for 6 and 24 hours, respectively.This study intended to formulate mosquito repellent paints based tobacco leaf extracts-free pyrethroid substance which is safe for users. The active substance which was added to the paint as a mosquito repellent was an extract of tobacco leaves. The result of Anti-mosquito paint formulation produced was according to the Indonesia National Standard (SNI). The results of anti-Aedes Aegypti mosquito paint effectiveness test showed that 5% concentration of tobacco extract could kill half of the mosquito population (LC50) for 2 hours, the concentration of tobacco extract between 3-5% killed half the mosquito population (LC50) during 4 hours, while 1-3% and 0-1% concentration of tobacco extract killed half the mosquito population (LC50) for 6 and 24 hours, respectively.

Selection of discrimination marker from various propolis for mapping and identify anti Candida albicans activity

The increase in fungal resistance against antifungal drugs available in the market will reduce the effectiveness of treatment for Candidiasis. Propolis contains various compounds with antifungal properties Candida albicans, but the content of each type is very diverse. The sample used was Sulawesi propolis type smooth (taken from inside the nest), rough (taken from outside the hive) and mix (a combination of both). Anti-C. albicans molecule marker is a marker compound for selecting propolis with the ability to overcome Candidiasis. The initial step was to test the levels of flavonoids and phenolic by using UV-Vis spectrometry method. It was founded that each sample was not always superior to any substance, so propolis cannot be directly selected. In Phenolic content, mix propolis has the highest value than other 5.109%. In Flavonoid content, propolis smooth has the highest value than other, 16.38%. Furthermore, propolis selected by antifungal activity test with good diffusion method at the concentration p...