Technological progress in biodiesel production: An overview on different types of reactors

2018 5th International Conference on Power and Energy Systems Engineering, CPESE 2018, 19–21 September 2018, Nagoya, Japan.Nowadays, research on biodiesel focuses on enhancing the conversion and production yield to fulfill the demand. Utilization of new feedstocks, development of highly efficient catalysts, determination of effective and economical reaction approaches, and application of process system engineering tools are efforts for the optimization purposes. This paper reviews the technological progress of reactors used for biodiesel production. The first part gives an overview of previous findings available in the literature. Many factors affecting the production yield of biodiesel have been reviewed such as reaction time, agitator rotational speed, temperature, types of catalyst, catalyst concentration, the molar ratio of oil and alcohol, types of solvent, and types of feedstock. However, the review of different types of reactors used for the biodiesel production is still lacking. The appropriate selection of reactor type is necessary to enhance the product yield and the productivity. Thus, the second part of this paper aims at compiling the information on various reactors. The description of key operating conditions and process design, relevant integrated reaction and separation techniques, recent achievement and progress, and challenges for future development are highlighted. This review provides the basis for exploitation and selection of reactor to enhance optimization, scale-up development, and implementation in industrial-scale biodiesel production

Sustainable production of second generation biocellulose and its green technology applications

Commonly, biocellulose was harvested from trees and cotton. However, Acetobacter xylinum, a gram-negative bacteria was discovered as being the microorganism capable of producing biocellulose by fermentation. This first generation of biocellulose is widely known as Nata whereby in Malaysia, this biocellulose was only produced as a dessert by food industries. However, there are some excellent properties of biocellulose make it able to be used in many fields. The modified biocellulose used for application other than dessert is defined as second generation biocellulose. This work aims to transfer the technology of a modified method for producing the second generation of biocellulose from bacteria. In this program, the designed Rotary Discs Reactor was being introduced to the company as a new method for biocellulose production. Efforts will be made with the help of the company to optimize and upscale the Rotary Discs Reactor for high production yield of biocellulose. This includes support for the expertise in fabricating, instrumentation, space and operational aspects. The biocellulose produced were further processed into a film for heavy metal removal in wastewater and powder as an additive in cement materials. This cooperation leads to a profitable outcome for the company by 30% improvement in the production rate of biocellulose compared to conventional static fermentation (tray methods) and opens for new applications of biocellulose. On the other hand, the company, university, and students gain benefits from sharing knowledge, facilities, intellectual properties, expertise, increase networking and at the same time enhance the graduate attributes for a future working environment

Process Parameters for Fermentation in a Rotary Disc Reactor for Optimum Microbial Cellulose Production using Response Surface Methodology

In this study, microbial cellulose production by Acetobacter xylinum 0416 using standardized liquid pineapple waste was carried out in a 4-L rotary disc reactor (RDR). The objective of this study was to optimize the process parameters for production of microbial cellulose in the RDR. The effects of the disc rotation speed (5 to 12 rpm), pH (3.5 to 7.5), fermentation period (3 to 6 days), and inoculum concentration (3 to 20% v/v) on the microbial cellulose production were investigated. The optimum microbial cellulose yield was obtained using 10% (v/v) of inoculum concentration, whereby four days’ duration gave the most productive yield. In addition, the highest production of microbial cellulose was obtained at a low disc rotation speed of 7 rpm and a pH of 5.0. Analysis of data performed a high coefficient of determination value (R2=0.875) represented by a mathematical model of optimized microbial cellulose production, Y = -200.437 + 7.180X1 + 69.869X2 + 4.369X3 + 1.867X4 – 0.512X12 – 6.766X22 – 0.585X32 – 0.079X42. From the results, it can be concluded that the foremost factors that affect the production of microbial cellulose in RDR were pH followed by inoculum concentration, disc rotation speed (rpm), and fermentation period

Monitoring the effect of pH on bacterial cellulose production and acetobacter xylinum 0416 growth in a Rotary Discs Reactor

Bacterial cellulose demonstrates unique properties including high mechanical strength, crystallinity and water retention ability that are suitable for industrial applications, such as food, paper manufacturing and pharmaceutical. In this study, Acetobacter xylinum 0416 was cultured in a designed 10-L Rotary Discs Reactor (RDR) to produce bacterial cellulose. The effects of different pH in the range of 3.5–7.5 on the bacterial cellulose production and the bacterial growth were investigated. The highest yield was obtained at pH 5.0 with a total dried weight of 28.3 g, while the lowest yield was obtained at pH 3.5 with a total dried weight of 4.7 g. Results also showed that the dried weight of bacterial cellulose was 60% higher when the pH of the medium was controlled during the experiments compared with uncontrolled pH. In addition, A. xylinum 0416 growth decreased to around 30% when pH value dropped from 5.05 to 3.56. The results also proved that the formation of acetic acid as a by-product caused the pH to drop during fermentation process in 10-L RDR

Effect of different drying methods on the morphology, crystallinity, swelling ability and tensile properties of nata de coco

Nata de coco or bacterial cellulose produced by Acetobacter xylinum is a unique type of biocellulose. It contains more than 90% of water. Dried nata was preferred compared to wet form since it is more convenient and portable with stable properties. Therefore, drying process is necessary in order to produce dried nata de coco. Drying method is a key factor that influenced the properties of dried nata de coco produced. The aim of this study was to investigate the effect of different drying methods on morphology, crystallinity, swelling ability and tensile strength of dried nata de coco. Nata de coco samples were dried using three physical drying methods such as oven, tray dryer or freeze dryer until it achieved 3-5% moisture content. Obviously, the three drying techniques produced web-like structured nata de coco and quite similar crystallinity which was in range between 87 and 89%. Freeze dried sample showed the largest swelling capacity and tensile strength which was found to be 148 MPa. Different drying method gave different properties of nata de coco. Therefore, the present work proposed the most suitable drying method can be utilized based on the properties of end product needed

Effect of irradiation time, solvent to solid ratio and power on microwave-assisted extraction of Colubrina asiatica

In the past decades, herbal plants had been used widely by indigenous or even urban people for disease treatment or taken orally as appetizers, including Colubrina asiatica (C. asiatica) or known as Peria Pantai. Previous studies reported that this plant contains a high amount of active compounds that are responsible for foaming ability and various bioactivities. However, these active compounds are sensitive towards many factors, temperature, pH, light, and others in the production line. Thus, this study was conducted to optimize the extraction conditions using microwave-assisted extraction (MAE) using Response Surface Methodology (RSM) and the Box-Behnken Design method was selected. The parameters used in RSM were irradiation time (3, 5, and 7 min), solvent to solid ratio (10, 20, and 30 mL/g), and power (300, 400, and 500 W). The optimal extraction for the extract was 6.06 min irradiation time, solvent to solid ratio 28.31 mL/g, and 445 W of microwave power provide 42.63 w/w %. The actual yield value from the experimental procedure was 43.1 ± 0.05 w/w %. The total saponin content of the extract was determined using Folin-Ciocaltaeu’s colorimetric method with a reading of 15.36 ± 0.001 mg ESE/mg

Potential use of biofibers for functional immobilization of lactobacillus rhamnosus NRRL 442

The present study aimed to characterize the agricultural residues of sugarcane bagasse {SB} and pineapple core {PC} for the use in immobilization of Lactobacillus rhamnosus NRRL 442. Using Standard Official Methods, SB and PC were found to contain approximately equal amount of nutrition content. The nutrition contents found include: 2.7-2.8 % of protein, 9.8-10 % of crude fiber, and 0.3-0.5 % of fat. On the other hand, SB demonstrated relatively higher solution holding capacity of 9.42 ± 2.3 g/g dry size sample than that of 6.04 ± 2.1 g/g dry size sample in PC. Under screening electron microscope, the fiber of SB has a flat and even surface; in contrast, the fiber of PC has a rough and overlapping surface which may promote the attachment or cell holding capacity during the immobilization process. However, the viability tests after cells immobilization have shown that SB provided higher cell survivability of 93.6 % than that of 64.1% in PC. These result highlighted the greater role of solution holding capacity of cellulose in ensuring a better cell survivability after immobilization process. As conclusion, this study showed the near future potentiality of SB and PC as immobilization carriers for Lactobacillus rhamnosus NRRL 442. It may substitutes proportionally of raw materials and be functional feed for ruminant

In situ modifications of bacterial cellulose film with pandanus amaryllifolius extract for heavy metal removal

Bacterial cellulose produced from the fermentation of Acetobacter xylinum present a high hydrophilicity and mechanical strength. These properties bring opportunities for the development of high quality paper, film and membrane. The morphology and properties of BC can be altered during the fermentation process. The in situ modifications were done by the addition of additives not specifically required for growth of the bacteria in the fermentation medium. Therefore, active materials can be incorporated into bacterial cellulose films for different applications. In this research, the pandan extract was added to the fermentation medium to produce Bacterial Cellulose-Pandan film. Pandan extract containing pyrroline that consists of cyclic nitrogen (-N=) and ketone, two functional groups that are responsible in metals biosorption. Different concentrations of extract were used to examine their impact on the cellulose production. Then, the films produced were tested with synthetic wastewater containing chromium VI to determine the heavy metal removal percentage. The result shows that increased concentration of pandan extract led to the increased of cellulose yield with proportional removal of heavy metal. In conclusion, in situ modifications during the fermentation process were successfully incorporated pandan extract into the bacterial cellulose fibrils. Hence, the combination of both properties could be used for the development of heavy metal removal materials in wastewater treatment

Characterization of bacterial cellulose produced via fermentation of acetobacter xylinum 0416

The production of plant-based cellulose products had contributed to the increasing rate of deforestation activities. Bacterial cellulose (BC) produced via fermentation process can be considered as an alternative. In this study, BC was produced by fermentation of Acetobacter xylinum 0416 and further analyzed to determine its physiochemical properties. The characterization of the BC was carried out through fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FESEM), thermogravimetric analysis (TGA), pH, moisture content, compressibility index and swelling properties. Then, it was compared with plant-based cellulose products which are carboxymethyl cellulose (CMC) and cellulose powder (CP). FTIR analysis demonstrated the similar properties between BC, CMC and CP while FESEM depicted a smoother surface and nanostructure of the BC. The TGA analysis indicated that BC has the highest thermal stability compared to CMC and CP. The other characterization results showed that BC displayed promising properties compared to CMC and CP. These findings further support the potential of substituting the use of plant-based cellulose products in the market with BC produced by A. xylinum 0416

Effect of pandan extract concentration to chromium (IV) removal using bacterial cellulose-pandan composites prepared by in-situ modification technique

Bacterial cellulose (BC) possesses high hydrophilicity and mechanical strength which suitable for the development of film, membrane and adsorbent materials. The morphology and properties of BC can be altered during fermentation by incorporation of additives not specifically required for the growth of bacteria in the fermentation medium. Therefore, active materials can be incorporated into BC matrices to form new composites for different applications. In this research, BC was produced from a static fermentation of Acetobacter xylinum. Applying the in-situ modification technique, pandan extract (PE) was added to the fermentation medium to form bacterial cellulose-pandan (BC-P) composite. PE contains 2-acetyl-1- pyrroline (2AP) compound consists of cyclic nitrogen and ketone groups that could be functional in metals biosorption. Different percentages of PE (25-100%) were added to examine their impact on the BC yield. Then, the BC-P composites were tested with synthetic wastewater containing chromium (VI) (Cr (VI)) for its removal study. The result shows that an increased percentage of PE added during fermentation led to the increased in BC yield. Consequently, the use of BC-P composites in the Cr(VI) removal studies resulted in the enhanced of removal efficiency up to 42% higher than the native BC. In conclusion, 2AP compound was successfully incorporated into BC matrices during fermentation by in-situ modification technique to form an active BC-P composite. Hence, the newly developed BC-P composites have presented excellent potential as an alternative for heavy metal removal in wastewater treatment