Application of matlab-based interface for the control of microbioreactor operation

This work presents the use of Arduino-based embedded system interfaced to MATLAB software packages as an alternative cost-effective solution for the control of the microbioreactor operation. In the presented work, a microbioreactor platform with a working volume of approximately 1.5 mL have been fabricated using a low-cost poly (methylmethacrylate) (PMMA) and poly(dimethylsiloxane) (PDMS) polymers. The reactor have been integrated with stirring control, fuzzy logic temperature control, and aeration feature via a miniature air compressor. Control program of the microbioreactor system was established using Simulink, MATLAB software were executed by interfacing the program with Arduino Mega 2560 microcontroller for input and output of signals. Numbers of experimentation were performed to validate and demonstrate the potential of the proposed method. Satisfactorily degree of control and supervision was achieved (± 1-3% of the set-point values). The entire microbioreactor system can be operated stably for a least 48 hours. The work demonstrated the usefulness of MATLAB software in establishing a microbioreactor operating interface that consisted merely few Simulink program block sets and executed on a low-cost Arduino board

Smartphone-based Wireless Operated Milliliter-scale Bioreactor

This paper presents the development of a smartphone-based wireless operated milliliter scale bioreactor. The bioreactor has a working volume of 18 mL and is made of poly (methylmethacrylate) (PMMA) and poly (dimethylsiloxane) (PDMS) polymers using a laser engraving methodology. Temperature and reactor stirring speed are the controlled variables and wireless communication is achieved through a wireless transceiver embedded in a low-cost controller platform. The results attained are very promising as the controller is able to control the desired reactor variables precisely through wireless communications

Solar-powered aquaponics prototype as sustainable approach for food production

This paper presents the establishment of a solar-powered aquaponics prototype as a sustainable, cost effective and environmentally sound approach for food production. In this study, a prototype bench top aquaponics rig with an integrated 20 W solar panel were fabricated for the cultivation of red Hybrid Tilapia (Oreochromis spp.) and leaf mustard (Brassica juncea). The size of the fish tank is about 29.5L and serves as the base for the setup. Additionally, the hydroponic grower compartment (0.45 m (L) � 0.32 m (W) � 0.13 m (H)) was stacked on top of the fish tank and was filled with LECA media bed for the plant growth. Two important operating parameters were studied. First, the amount of energy produced by the solar panel and the energy consumption by the water pump used in the setup. Secondly, the resultant effects from fish cultivation and plants growth on the water qualities and nitrification effi�ciency of the aquaponics unit. The aquaponics unit was operated for a month and the values of pH, tem�perature, and ammonia level were measured to be within the range of 6.4–7.2, 27.1–31.7 �C, and 1 mg�L�1 , respectively. Survival rate for fish was about 75% with specific growth rate (SGR) of 3.75% per day and food conversion ratio of about 1.15. A slight nutrient deficiency was evident and plants showed a healthy growth with height gain as high as 5 cm was achieved. Despite raining season, our data shows that the energy produced via 20 W solar panel enabled the unit to run at night without depending on local electricity for nearly two hours. Clearly, a larger solar panel is needed for longer operation. Nevertheless, the study has proven the potential of operating a low cost aquaponics setup using renew�able energy for a sustainable food production method

Sterilizable miniature bioreactor platform for anaerobic fermentation process

This paper presents the establishment of a miniature bioreactor platform for anaerobic microbial fermentation processes. It is made from a universal glass bottle and has a working volume of 16 mL. Reactor features included mixing via magnetic stirrer, temperature control via electrical heater and cells optical density (OD) sensing. All sensors and actuators integrated into the reactor were operated using LabVIEWTM (National Instrument, TX, US). The top lid of the bottle was modified to include a 3mm poly(methylmethacrylate) (PMMA) polymer layer where it was machined to provide spaces for fluidic ports and integration of sensors. Each reactor components were sterilized prior to conducting fermentation experiments. Main body of the reactor was made of glass and it was sterilized using the standard heat sterilization method (121°C for 15 minutes) where else other components were sterilized by exposure to UV light for 2 hours. A series of anaerobic fermentation experiments were conducted in batch mode using S.cerevisiae to evaluate the workability of the system. Fermentation experiments were conducted using inoculum concentration of 2 g L-1 and starting glucose concentration between 10 g L-1 and 20 g L-1. In every experiment, mixing was set to operate at 400 rpm and temperature was adjusted to 30 ± 2°C. Experiments were carried out until stationary phase was attained. Under these conditions, the best fermentation profile was obtained with glucose concentration of 20 /L where cell specific growth rate was found to be about 0.28 h-1. Bench marking step was also performed where results attained in a miniature bioreactor platform were comparable with the one attained using a 50 mL flask

A miniature membrane reactor for evaluation of process design options on the enzymatic degradation of pectin

The objective of this paper is to assess if a membrane microbioreactor system could potentially be used to diagnose consequences of different process design and reactor operation options relevant for larger-scale enzymatic degradation of pectin reactions. The membrane microbioreactor prototype was fabricated from poly(methylmethacrylate) (PMMA) and poly(dimethylsiloxane) (PDMS) with a working volume of ~190 µL. The prototype also contained the necessary sensors and actuators, i.e., pressure transducer, mixing via magnetic stirrer bar and a temperature controller. The functionality of the prototype was demonstrated by performing a continuous enzymatic degradation of pectin experiment for a range of reactor conditions: different membrane molecular weight cutoff (MWCO) values, enzyme-to-substrate ratios (E/S), and substrate feeding rates (F) were assessed. Based on the experimental data, it was found that the apparent reaction rate increased from 0.11 µmol/h to 0.13 µmol/h when the E/S ratio was doubled from 0.2% (g/g) to 0.4% (g/g). In contrast, when the substrate feeding rate was reduced from 200 µL/h to 100 µL/h (i.e., longer residence time), a higher yield was achieved (producing a pectin fragment concentration of 0.82 mM in the permeate) and the apparent reaction rate increased by ~50% (i.e., from 0.11 µmol/h to 0.17 µmol/h). Clearly, this signifies that the substrate feeding rate is a critical variable that influences the conversion rate and the process yield. The data also showed that the process design affected the membrane rejection profile. The results obtained thus underlined the suitability of a miniature membrane reactor system for evaluating different process design options that are relevant for larger-scale reactions of enzymatic pectin degradation

Carbonized rice husk and cocopeat as alternative media bed for aquaponic system

The study evaluates the suitability of carbonized rice husk and cocopeat substrates as alternative media bed in aquaponics unit for cultivation of red Nile tilapia and Gynura procumbens. Area occupied by the aquaponics unit is about 4.5 m2 and it was operated under equatorial climate conditions. Various substrates namely lightweight expanded clay aggregate (LECA), cocopeat, carbonized rice husk and a mixture of cocopeat-rice husk at ratio 1:1 were prepared using polybags for growing of the longevity spinach. The resultant effects from fish cultivation and plants growth on the water qualities and nitrification efficiency of the aquaponics unit were reported. The aquaponics unit were operated for twelve weeks and the values of pH, temperature, and dissolved oxygen level were measured to be within the range of 6.4-6.9, 27.7-29oC, and 5.5-7 mg·L-1, respectively. Survival rate for fish was 98% with specific growth rate (SGR) and food conversion ratio (FCR) of 6.9% per day and 1.13, respectively. Nutrient deficiency was not evident and plants showed healthy growth with harvest yield ranging between 3.6 and 3.9 kg·m-2. Results attained signified the suitability of utilizing carbonized rice husk and cocopeat as alternatives media bed compared to commercial media bed such as LECA

A portable sensor for cell optical density measurement in microfluidic chips

This paper presents the development of a smartphone-controlled wireless device for cell optical density sensing in microfluidic chips. The footprint of the device is very compact relative to a classical laboratory spectrophotometer, making it a portable device. The cell optical density sensing device consists of an embedded microcontroller, optical sensing components, and a wireless transceiver performing cell optical density measurements in disposable microfluidic chips fabricated from poly(methylmethacrylate) polymers. The device is controlled by an Android application allowing for true portability and the possibility of remote or field operation of the device. The use of microfluidic chips as the sample carrier for optical density detection instead of a plastic cuvette allows users the flexibility to explore and/or conduct a variety of micro-scale chemical analysis using the device which would be difficult in a cuvette-based system. The function of the device is validated through a series of off-line and online optical density measurements using Saccharomyces cerevisae yeast cultures. The device is low cost, small enough to fit in most laboratory flow hood cabinets, and can be easily integrated into miniature bioreactor systems. Moreover, wireless communication enables the user to operate the device using smartphones or rapidly transfer the measured data to an online repository for analysis or storage

The effects of conventional and microwave heating techniques on extraction yield of orthosiphon stamineus leaves

The heating technique in a solid-liquid extraction system plays a significant role in the design and economic potential for the extraction of active components from herbs. This paper focused on the effects of extraction parameters such as ratio of sample to solvent, temperature and time of processing on the extraction yield of Orthosiphon stamineus leaves in conventional and microwave heating extraction techniques. The extracts were concentrated and dried using a rotary evaporator and freeze dryer in order to relate the yield to the processing parameters quantitatively in both heating techniques. The analysis results revealed that the processing parameters; ratio of sample to solvent, temperature and time of extraction had essential effects on the extraction yield of Orthosiphon stamineus leaves. Microwave heating extraction produced a comparable yield to conventional heating extraction with a relatively small deviation of approximately 2.8 % in average. Furthermore, microwave heating extraction reduced processing time, where this technique required about 25 % of the conventional heating time in heating up the extraction mixture to set-point temperature (60 ºC). This study concludes that microwave heating extraction, which is a green technology, has great potential in reducing the carbon foot print due to a shorter processing time and reduced energy consumption (~77 % less) compared to conventional heating extraction

Prototyping of polymer based microbioreactors: micromachining by using poly(methyl methacrylate) and poly(dimethylsiloxane) polymer materials

Polymers have been widely accepted as materials for the fabrication of microbioreactor prototypes. In this work, microfabrication strategies namely the micromachining and casting (soft lithography) with the use poly(methyl methacrylate) (PMMA) and poly(dimethylsiloxane) (PDMS) polymers as substrates for fabrications were discussed in details. A step-by-step illustration (including examples on digital prototyping of the microbioreactor by using a computer-aided-design (CAD) software) for the above mentioned micromachining procedures, and discussions on the necessary design considerations were presented as well. In the work, we showed the simplicity of such machining procedures for the fabrication of microbioreactor prototypes. It was confirmed that through micromachining, microbioreactor prototypes can be fabricated by using poly(methyl methacrylate) (PMMA) and poly(dimethylsiloxane) (PDMS) polymers with high precision (down to one tenth of mm). It was also demonstrated that the processing time for the fabrication of the microbioreactor prototypes was in the order of few hours and maybe days for a complex reactor design