Bioreactor Volume Research Articles

Adding Zooplankton to the OSMAC Toolkit: Effect of Grazing Stress on the Metabolic Profile and Bioactivity of a Diatom

“One strain many compounds” (OSMAC) based approaches have been widely used in the search for bioactive compounds. Introducing stress factors like nutrient limitation, UV-light or cocultivation with competing organisms has successfully been used in prokaryote cultivation. It is known that diatom physiology is affected by changed cultivation conditions such as temperature, nutrient concentration and light conditions. Cocultivation, though, is less explored. Hence, we wanted to investigate whether grazing pressure can affect the metabolome of the marine diatom Porosira glacialis, and if the stress reaction could be detected as changes in bioactivity. P. glacialis cultures were mass cultivated in large volume bioreactor (6000 L), first as a monoculture and then as a coculture with live zooplankton. Extracts of the diatom biomass were screened in a selection of bioactivity assays: inhibition of biofilm formation, antibacterial and cell viability assay on human cells. Bioactivity was found in all bioassays performed. The viability assay towards normal lung fibroblasts revealed that P. glacialis had higher bioactivity when cocultivated with zooplankton than in monoculture. Cocultivation with diatoms had no noticeable effect on the activity against biofilm formation or bacterial growth. The metabolic profiles were analyzed showing the differences in diatom metabolomes between the two culture conditions. The experiment demonstrates that grazing stress affects the biochemistry of P. glacialis and thus represents a potential tool in the OSMAC toolkit.

Cultivation of Saccharomyces cerevisiae with Feedback Regulation of Glucose Concentration Controlled by Optical Fiber Glucose Sensor.

Glucose belongs among the most important substances in both physiology and industry. Current food and biotechnology praxis emphasizes its on-line continuous monitoring and regulation. These provoke increasing demand for systems, which enable fast detection and regulation of deviations from desired glucose concentration. We demonstrated control of glucose concentration by feedback regulation equipped with in situ optical fiber glucose sensor. The sensitive layer of the sensor comprises oxygen-dependent ruthenium complex and preimmobilized glucose oxidase both entrapped in organic–inorganic polymer ORMOCER®. The sensor was placed in the laboratory bioreactor (volume 5 L) to demonstrate both regulations: the control of low levels of glucose concentrations (0.4 and 0.1 mM) and maintenance of the glucose concentration (between 2 and 3.5 mM) during stationary phase of cultivation of Saccharomyces cerevisiae. Response times did not exceed 6 min (average 4 min) with average deviation of 4%. Due to these regulation characteristics together with durable and long-lasting (≥2 month) sensitive layer, this feedback regulation system might find applications in various biotechnological processes such as production of low glucose content beverages.

Overcoming bioprocess bottlenecks in the large-scale expansion of high-quality hiPSC aggregates in vertical-wheel stirred suspension bioreactors

BackgroundHuman induced pluripotent stem cells (hiPSCs) hold enormous promise in accelerating breakthroughs in understanding human development, drug screening, disease modeling, and cell and gene therapies. Their potential, however, has been bottlenecked in a mostly laboratory setting due to bioprocess challenges in the scale-up of large quantities of high-quality cells for clinical and manufacturing purposes. While several studies have investigated the production of hiPSCs in bioreactors, the use of conventional horizontal-impeller, paddle, and rocking-wave mixing mechanisms have demonstrated unfavorable hydrodynamic environments for hiPSC growth and quality maintenance. This study focused on using computational fluid dynamics (CFD) modeling to aid in characterizing and optimizing the use of vertical-wheel bioreactors for hiPSC production.MethodsThe vertical-wheel bioreactor was modeled with CFD simulation software Fluent at agitation rates between 20 and 100 rpm. These models produced fluid flow patterns that mapped out a hydrodynamic environment to guide in the development of hiPSC inoculation and in-vessel aggregate dissociation protocols. The effect of single-cell inoculation on aggregate formation and growth was tested at select CFD-modeled agitation rates and feeding regimes in the vertical-wheel bioreactor. An in-vessel dissociation protocol was developed through the testing of various proteolytic enzymes and agitation exposure times.ResultsCFD modeling demonstrated the unique flow pattern and homogeneous distribution of hydrodynamic forces produced in the vertical-wheel bioreactor, making it the opportune environment for systematic bioprocess optimization of hiPSC expansion. We developed a scalable, single-cell inoculation protocol for the culture of hiPSCs as aggregates in vertical-wheel bioreactors, achieving over 30-fold expansion in 6 days without sacrificing cell quality. We have also provided the first published protocol for in-vessel hiPSC aggregate dissociation, permitting the entire bioreactor volume to be harvested into single cells for serial passaging into larger scale reactors. Importantly, the cells harvested and re-inoculated into scaled-up vertical-wheel bioreactors not only maintained consistent growth kinetics, they maintained a normal karyotype and pluripotent characterization and function.ConclusionsTaken together, these protocols provide a feasible solution for the culture of high-quality hiPSCs at a clinical and manufacturing scale by overcoming some of the major documented bioprocess bottlenecks.

Manufacturing T cells in hollow fiber membrane bioreactors changes their programming and enhances their potency

ABSTRACT Engineered T cell therapies have revolutionized modern oncology, however processes for manufacturing T cell therapies vary and the impact of manufacturing processes On the cell product is poorly understood. Herein, we have used a commercially available hollow fiber membrane bioreactor (HFMBR) operated in a novel mode to demonstrate that T cells can be engineered with lentiviruses, grown to very high densities, and washed and harvested in a single, small volume bioreactor that is readily amenable to automation. Manufacturing within the HFMBR dramatically changed the programming of the T cells and yielded a product with greater therapeutic potency than T cells produced using the standard manual method. This change in programming was associated with increased resistance to cryopreservation, which is beneficial as T cell products are typically cryopreserved prior to administration to the patient. Transcriptional profiling of the T cells revealed a shift toward a glycolytic metabolism, which may protect cells from oxidative stress offering an explanation for the improved resistance to cryopreservation. This study reveals that the choice of bioreactor fundamentally impacts the engineered T cell product and must be carefully considered. Furthermore, these data challenge the premise that glycolytic metabolism is detrimental to T cell therapies.

Application of biomagnetic nanoparticles for biostimulation of biogas production from wastewater treatment

This study presents biomagnetic nanoparticles (BMNPs) as a biostimulant for wastewater treatment and biogas upgrading to natural quality (>90% CH4). Notwithstanding, application of anaerobic digestion (AD) in wastewater settings is still limited with slow kinetics and low methanation yield. Here, four BMNPs (CuO, Fe2O3, TiO2, Cu/Fe-TiO2) were investigated to enhance the high-rate anaerobic system for complete degradation of organic waste to value – added products (water and biogas). Sugar refinery wastewater was used as a substrate and activated sludge as inoculum. This was carried out in 800 mL working volume bioreactors at a mesophilic temperature of 35 °C and hydraulic retention time of 30 days. Results showed the substrate – inoculum degradation in the control system, when induced with the BMNPs increased the methane (CH4) potential from 63% to 100%. Likewise over 75% water index of chemical oxygen demand, total suspended solids, and volatile solids were removed. Stimulatingly, the biogas production and wastewater treatability was significantly improved upon adding the BMNPs to the bioreactors which enriched the methanogenic activities. The post-sludge analysis showed the morphological and elemental distribution of the BMNPs, and their biomagnetic interactions with the micobes which enhanced the adsorptive removal of the contaminants and the biogas production yield. The Gompertz modified kinetic model significantly (P < 0.05) favoured the cumulative biogas yield obtained for all the bioreactors with a kinetic rate constant within the range of 0.182504–0.203027 d-1. The performance of Cu/Fe-TiO2 additives superseded the rest of the BMNPs. In conclusion, BMNPs revealed economic prospects of regeneration and reuse with external magnets for effective wastewater treatment.

Towards the Anaerobic Production of Surfactin Using Bacillus subtilis

The anaerobic growth of B. subtilis to synthesize surfactin poses an alternative strategy to conventional aerobic cultivations. In general, the strong foam formation observed during aerobic processes represents a major obstacle. Anaerobic processes have, amongst others, the distinct advantage that the total bioreactor volume can be exploited as foaming does not occur. Recent studies also reported on promising product per biomass yields. However, anaerobic growth in comparison to aerobic processes has several disadvantages. For example, the overall titers are comparably low and cultivations are time-consuming due to low growth rates. B. subtilis JABs24, a derivate of strain 168 with the ability to synthesize surfactin, was used as model strain in this study. Ammonium and nitrite were hypothesized to negatively influence anaerobic growth. Ammonium with initial concentrations up to 0.2 mol/L was shown to have no significant impact on growth, but increasing concentrations resulted in decreased surfactin titers and reduced nitrate reductase expression. Anaerobic cultivations spiked with increasing nitrite concentrations resulted in prolonged lag-phases. Indeed, growth rates were in a similar range after the lag-phase indicating that nitrite has a neglectable effect on the observed decreasing growth rates. In bioreactor cultivations, the specific growth rate decreased with increasing glucose concentrations during the time course of both batch and fed-batch processes to less than 0.05 1/h. In addition, surfactin titers, overall YP/X and YP/S were 53%, ∼42%, and ∼57% lower than in serum flask with 0.190 g/L, 0.344 g/g and 0.015 g/g. The YX/S, on the contrary, was 30% lower in the serum flask with 0.044 g/g. The productivities q were similar with ∼0.005 g/(g⋅h). However, acetate strongly accumulated during cultivation and was posed as further metabolite that might negatively influence anaerobic growth. Acetate added to anaerobic cultivations in a range from 0 g/L up to 10 g/L resulted in a reduced maximum and overall growth rate μ by 44% and 30%, respectively. To conclude, acetate was identified as a promising target for future process enhancement and strain engineering. Though, the current study demonstrates that the anaerobic cultivation to synthesize surfactin represents a reasonable perspective and feasible alternative to conventional processes.

Simulating of Microbial Growth Scale Up in a Stirred Tank Bioreactor for Aerobic Processes using Computational Fluid Dynamics

In this paper, the effects of some empirical scale up criteria (Reynold's number and Impeller power per bioreactor volume) on gas-liquid mass transfer and microbial growth rates are analyzed using computational fluid dynamics simulations in a stirred tank bioreactor. The effects of turbulence, fluid flow and bubbles dynamics were simulated by using a two equation turbulence model, a multiple reference frame and a population balance, respectively. The impeller power per bioreactor volume scale up criterion showed better microbial growth rates than Reynold's number scale up criterion. However, high cellular damage due to turbulence in animal cell culturing are still challenges in large scale up bioreactor prototyping.

Economic evaluation of M13 bacteriophage production at large‐Scale for therapeutic applications using aqueous Two‐Phase systems

AbstractBACKGROUNDBacteriophages are bionanoparticles with several applications in different biotechnology‐based products. Among them, vaccines have the potential to treat antibiotic‐resistant bacteria and parasitic infections. Traditional methods for their recovery and purification rely on precipitation with polyethylene glycol (PEG) and NaCl. However, the applicability of such an approach is limited, due to large‐scale technical constrains. Recently, our research group developed a bacteriophage M13 recovery and purification strategy using Aqueous Two‐Phase Systems (ATPS), simplifying the methodology and, potentially, reducing costs. This work aims to develop an economic contrast between ATPS and the traditional PEG precipitation method at different operation scales (10 to 1000 L bioreactor volume) to determine the applicability of the ATPS methodology at large scale. For this, the effect of ATPS volume ratio (VR), sample loading, and materials discount over production cost were analyzed.RESULTSResults indicate that as the discount on material costs increases, ATPS becomes a more affordable unit operation, from a bioreactor scale of 10 L at 0% discount to 410 L at 90% discount (US$ 52.2 to $1.72 per gram, respectively). Material cost contribution is a parameter that needs attention when working with ATPS, as it is the core for the system construction. Methods for reducing their contribution are highly relevant and should be further investigated.CONCLUSIONEmployment of economic analyses help to discover critical parameters for a bioprocess, such as material costs for ATPS. This economic analysis work serves as a platform for new strategies for the recovery of bacteriophage and bacteriophage‐like particles using ATPS‐based technologies. © 2020 Society of Chemical Industry (SCI)

Investigation of cell line specific responses to pH inhomogeneity and consequences for process design.

With increasing bioreactor volumes, the mixing time of the reactor increases as well, which creates an inhomogeneous environment for the cells. This can result in impaired process performance in large‐scale production reactors. Particularly the addition of base through the reactor headspace can be problematic, since it creates an area, where cells are repeatedly exposed to an increased pH. The aim of this study is to simulate this large‐scale phenomenon at lab‐scale and investigate its impact. Two different cell lines were exposed to pH amplitudes of a maximal magnitude of 0.05 units (pH of 6.95). Both cell lines showed similar responses, like decreased viable cell counts, but unaffected lactate levels. However, cell line B showed an initially increased specific productivity in response to the introduced amplitudes, whereas cell line A showed a consistently lower specific productivity. Furthermore, the time point at which base addition is started influences the impact, which pH amplitudes have on process performance. When pH control was started earlier in the process, maximal viable cell counts decreased and the lactate metabolic shift was less pronounced. These results show that the potential negative impact of pH amplitudes can be minimized by strategic process design.

Modeling and performance prediction of a conceptual bioprocess for mass production of suspended stem cells

It is essential to design bioprocesses which provide appropriate conditions for stem cell growth from low initial amounts to desirable values. For this purpose, a simple and efficient conceptual bioprocess based on a stirred tank bioreactor containing an inner tube with sequencing batch aeration system was designed, and modeled for performance prediction of mass production of suspended stem cells. Based on the bioprocess design parameters as well as cell characteristics and final cell density, overall volume of bioreactor required for both liquid and gas phases was selected equal to 400 ml including an inner tube with diameter and height of 2 cm and 10 cm, respectively. Aeration system was considered according to consumption rate of O2 and production rate of CO2 as daily replacement of total gas phase (with 1% positive pressure). Medium exchange was also considered as replacement of half of the liquid phase with a new medium every three-day. The bioprocess was then modeled after writing related mass balances and the system performance was predicted for a 10-day culture period. The designed bioreactor system predicted that the final number of cells needed by the patient can be achieved during the 10-day cultivation from small biopsy without the problems caused by shortage or critical accumulation of any materials. The conceptual bioprocess modeling and performance prediction showed a great potential to examine the culture system for suspended stem cell production.

Nitrate removal and secondary effects of a woodchip bioreactor for the treatment of subsurface drainage with dynamic flows under pastoral agriculture

While enabling economically viable use of poorly drained soils, artificial subsurface drainage has also been found to be a significant pathway for nutrient transfers from agricultural land to surface waters. Thus, mitigating the impacts of agriculture on surface water quality needs to address nutrient transfers via subsurface drainage. Woodchip bioreactors are a promising mitigation option as demonstrated under arable agriculture in the mid-west of the USA. However, research is needed to ascertain their efficiency in removing nutrients from very flashy drainage flows common in New Zealand (NZ) pastoral agriculture and any possible pollution swapping (e.g. reduction of leaching losses vs. greenhouse gas emissions). Accordingly, a lined 78-m3 woodchip bioreactor was constructed on a dairy farm in the Hauraki Plains (Waikato, NZ) with a drainage area of 0.65 ha. Rainfall, flow, hydrochemistry and dissolved gases in the inflow and outflow were monitored for two drainage seasons (part of 2017, 2018). Based on the nitrate-N fluxes, the estimated nitrate removal efficiency of the bioreactor was 99 and 48% in 2017 and 2018, respectively. The higher removal efficiency in 2017 could be attributed to two reasons. Firstly, the substantially longer hydraulic residence time (HRT) of the water in the bioreactor (mean = 21.1 days vs 4.7 days in 2018) provided more opportunity for microorganisms to reduce the nitrate. A strong positive relationship between HRT and removal efficiency was also observed within the 2018 drainage season. Secondly, denitrification was supported in 2017 by greater electron donor availability. Evidence of this was the higher mass of DOC discharge from the bioreactor (318 mg C L−1 of bioreactor volume vs 165 mg C L−1 in 2018). Removal rates in the bioreactor varied from 0.67–1.60 g N m−3 day−1 and were positively correlated with inflow nitrate loads. Pollution swapping was observed during the start-up phase of the bioreactor in both years (DOC, and DRP only in 2017) and during periods with very long HRTs (hydrogen sulphide (H2S) and methane (CH4) production). Substantially elevated discharges of DOC and DRP, as compared to inlet conditions, occurred during the initial start-up phase of the bioreactor in 2017 (3 to 3.5 pore volumes of the bioreactor), but only slightly elevated DOC and decreased DRP discharges were observed when drainage flow resumed at the start of the 2018 drainage season. Unexpectedly, cumulative DRP removal during the 2018 drainage season amounted to 89% of the DRP inflow into the bioreactor. Long HRTs (>5 days) enabled high nitrate removal efficiency (≥59%) and promoted complete reduction of nitrate to harmless dinitrogen gas but also promoted strongly reduced conditions, resulting in the production of H2S and CH4. On the other hand, short HRTs (<4 days) only allowed for moderate nitrate removal efficiency (≤43%) and constrained complete reduction of nitrate resulting in higher nitrous oxide concentrations in the outflow as compared to the inflow. Thus, nitrate removals above 50% were not able to be achieved without inducing H2S and CH4 generation. However, it may be achievable when the microbial community is provided with an additional source of readily available carbon during the critical periods when hydraulic flow and concomitant N load peaks occur.

Bioprocessing of shrimp wastes to obtain chitosan and its antimicrobial potential in the context of ethanolic fermentation against bacterial contamination.

This study investigated the bioprocessing of shrimp wastes to obtain chitin and its deacetylated product chitosan by a fermentation process mediated by Lactobacillus plantarum. The concentrations of glucose, bacterial inoculum, and shrimp wastes in the Man, Rogosa and Sharpe medium were optimized for the fermentation process performed in shake flasks to achieve the maximum titratable acidity to obtain chitin. The experiments were scaled up in a 700-mL working volume bioreactor, and the resulting chitin was deacetylated by the autoclave method. The bioextracted chitosan was characterized (Fourier transform infrared spectroscopy [FTIR], deacetylation degree, and molecular weight) and evaluated for its antimicrobial effects by comparing it with a commercial chitosan sample in the context of the ethanolic fermentation process for fuel alcohol production. The effect of chitosan on such a fermentation process has not been determined yet. The bacterial contaminant Lactobacillus fermentum and the main agent of ethanolic fermentation Saccharomyces cerevisiae were cultured in semi-synthetic medium and co-cultured in sugarcane juice to verify the effect of chitosan on their growth. The bioextracted chitosan (molecular weight 4.0 × 105gmol-1 and deacetylation degree 80%) was comparable to commercial chitosan, although higher concentrations of the former were required to achieve similar antimicrobial activities. Both commercial and bioextracted chitosan samples exhibited antimicrobial activity against S. cerevisiae and L. fermentum, but the concentration that caused the inhibition of yeast growth was almost tenfold higher than for the bacterium. Moreover, bioextracted chitosan showed no yeast inhibition or lethality in the range of 0.0075-0.96% while for the bacterium, growth inhibition occurred in concentrations varying from 0.24 to 0.48% and lethality of more than 99% at 0.96%. These results indicate the potential use of chitosan and especially of bioextracted chitosan in the bioethanol industry as a safer and more natural approach to combat unwanted bacterial contamination.

Fed Intermittent Composting of Food Waste from Minor Touring City, Using Reactors with Different Passive Ventilation

The purpose of this study is to evaluate the influence of air on the decomposition of food waste from minor touring city of Thailand using composting bioreactors with different ventilation. The reactors were made from 200L PE plastic bioreactors. There were 5 different bioreactors, each with a different vent volume. (These were 0%, 2.3%, 3%, 4.3% and 5.7% of bioreactor volume or 0, 1, 2, 4 and 6 PVC pipes of diameter 1¼", respectively. Each reactor also had a drain. The material to be composted was food scraps ground to a size less than 1.5 cm and mixed with rice husk, ash and saw dust at a ratio of 6: 1: 1 to achieve a C / N ratio of 35: 1. The Intermittently-Fed Composting (FIC) method was used, adding 4.5 kilograms of materials per day until 85 kg was added in total. The experiment was also subdivided into 2 types: bioreactors with added microbes (added-PD2); and those without added microbes (non-PD2). The experiment had a 60-day biodegradation period. Measurements of temperature, moisture content, and pH were taken and compost samples were analyzed for their germination index (GI) and quality, compared with Thailand compost standards. The results showed that the optimum air volume for composting was 3% of bioreactor volume, or 2 pipes. The composting time was 19 days with the highest temperature of 57-58°C and the temperature was held constant for 33 days. The organic waste decomposition and curing took a total of 57 days, with a GI value between 79-81% and the quality of the resulting fertilizer complied with standards. The main minerals in the compost were N, P and K, which were 1.25% -1.32%, 0.69% -0.76% and 0.93% -1.88%, respectively. It is concluded that different ventilation ratios affect the results for the decomposition of organic matter, with optimal ventilation being 3.0% of bioreactor volume or 2 pipes. There was a statistically significant difference between the results for compost with and without the addition of PD2.

Production of Cellulase and Xylanase Enzymes Using Distillers Dried Grains with Solubles (DDGS) by Trichoderma reesei at Shake-Flask Scale and the Validation in the Benchtop Scale Bioreactor

Most of the corn-ethanol plants use dry-mill process and generate large volume of distillers dried grains with solubles (DDGS) as the co-product. The DDGS is a promising feedstock with rich content of cellulose and xylan. The goal of this study was to optimize cellulase and xylanase production by Trichoderma reesei (NRRL 6156) using DDGS as the carbon source at shake-flask and validate the results at benchtop bioreactors. The fermentation medium containing varied amounts of dilute-acid pretreated DDGS, yeast extract, and peptone were optimized for maximal enzyme production at 30 °C, pH 5.0 and 180 rpm with 3% (v/v) inoculum using Box-Behnken response surface methodology (RSM). Co-production of xylanase and cellulase enzymes was not achieved in the same medium; higher DDGS hydrolysate favored cellulase enzyme only while lower amount induced the xylanase enzyme. Based on the RSM results, maximal xylanase of 18.5 IU/mL was predicted with 5% DDGS hydrolysate, 0.1 g/L yeast extract, and 2 g/L peptone, while maximal cellulase of 1.1 IU/mL was predicted with 20% DDGS hydrolysate, 1 g/L yeast extract, and 0.5 g/L peptone. Of the two developed models from shake-flasks, xylanase model validated successfully the fermenter results giving 18.7 IU/mL of experimental xylanase in 1.5-L working volume bioreactor.

The application of novel magnetically coupled mixer drives in bioreactors of up to 15 m3

We introduce a novel magnetically coupled mixer drive for biotechnological, pharmaceutical and chemical applications requiring high-grade aseptic conditions. The proposed design enables its application in larger volume bioreactors compared to traditional magnetic drives, due to a possibility of introducing higher power quantities per individual rotor, while ensuring higher mixing intensity.In the following study, we provide information on the design aspects of the novel magnetic drive and demonstrate the principles behind both theoretical and experimental maximal torque and other key working parameter evaluation. Based on the mentioned principles, magnetic mixer drives were developed for laboratory (5 dm3) and pilot-scale (15 m3) bioreactors. The specific power inputs relative to the agitation rates for the mentioned mixers were experimentally determined in water for two impeller types: six-bladed Rushton and three-bladed Pitched-blade turbines. The performance of the novel magnetic drive was evaluated during Kluyveromyces marxianus cultivations utilizing whey (a well known byproduct of the dairy industry) as the main substrate source in the 15 m3 bioreactor.The obtained results show that the novel magnetic drive can be successfully applied in 15 m3 bioreactors, while providing sufficient mixing of the cultivation broth for biomass growth.

The Implementation of Biofloc Systems in the Catfish Breeding Cooperated with Lele Tamora SME

This community service aims to provide solutions for fisheries that experience water change problems caused by the lower availability of ground water. The small-medium enterprise (SME) Lele Tamora which is engaged in catfish breeding experiences this problem, such as turbid and bubbly water, which causes mass death of fish seedlings. Therefore, pond fish farming with a modern system integrated by a biofloc system that is supported by the use of microbubbles is introduced to the owner. The basic principle of this system is to utilize bacteria that can release substances that function as adhesives to form biofloc, such as microalgae aggregates, residual pellets, exoskeletons of dead organisms, bacteria, protists, protozoa and others substance with 0.1-2 mm diameter. All of these aggregates can be a source of poison in the pond system or as a competitor for fish to get oxygen. The biofloc system is projected to be able in reducing the toxic content in pond water which automatically reduces fish mortality, and this system can also convert organic waste in ponds into natural food as well as reducing commercial feed. For this purpose, a 1000 liter volume of bioreactor has been constructed to grow biofloc bacterial seeds, 20-liter-capacity of autoclaves to sterilize dissolved oxygen while helping to breed floc-forming aerobic bacteria. This system has been implemented at Lele Tamora SME, and the results showed the changing of water-pond colour from green to brown. Meanwhile, the netting ratio (selection of catfish based on the size of ready-to-sell) increased from 4000 to 8000 individuals.

The performance of a pilot-scale anaerobic hybrid bioreactor on palm oil mill effluent treatment

Contemporarily, Indonesia and Malaysia are the largest contributors of crude palm oil (CPO) in the world by up to 40%, and 37.3%, respectively. Furthermore, its production value this year reached 19.7 million tons, where each generates 2.5 m3 of wastewater. Meanwhile, of all the provinces in Indonesia specifically, Riau is the largest supplier for exports by up to 38%, generated from 225 palm oil mills, where a total of 6.3 million tons resulting in the generation of about 15.75 million m3 of wastewater, with organic content between the range of 30,000-60,000 mg COD/l. In addition, one of the uses of this wastewater includes anaerobic processes, with the double benefit of reducing COD concentrations, subsequently applying it as fertilizer, and also in the production of methane gas, as an alternative source of energy. The purpose of this study, therefore, is to observe the effect of bioreactor volume, scale-up on the performance of anaerobic hybrid bioreactors, in the treatment of mill effluents. The technology examined in this study was the anaerobic hybrid bioreactor with the dimensions of length 22 m, width 10 m, and depth 1.5 m, and a total volume of 330 m3, which is impermeable to oxygen, and a 250 m3 effective working volume. This was built and operated at a hydraulic retention time of 1 day, in the Palm Oil Mill of Riau, and the results showed the environmental conditions to range from a pH of 7.2 to 8.0, with temperatures from 320C to 350C, acetic acid of 774 mg/l to 1,180 mg/l, and alkalinity of 2,149 mg/l up to 2,400 mg/l. Furthermore, the performance of these reactors are shown by the highest COD removal efficiency of 77.8%, and a biogas test for the propensity of being applied as an alternative energy source obtained a methane gas concentration of 54%. Keywords: anaerobic, bioreactor, biogas, wastewater, performance, palm oil mill effluent

Bioproduction of High-Concentration 4-Vinylguaiacol Using Whole-Cell Catalysis Harboring an Organic Solvent-Tolerant Phenolic Acid Decarboxylase From Bacillus atrophaeus.

The compound 4-vinyl guaiacol (4-VG) is highly valued and widely applied in the pharmaceutical, cosmetic, and food industries. The bioproduction of 4-VG from ferulic acid (FA) by non-oxidative decarboxylation using phenolic acid decarboxylases is promising but has been hampered by low conversion yields and final product concentrations due to the toxicities of 4-VG and FA. In the current study, a new phenolic acid decarboxylase (BaPAD) was characterized from Bacillus atrophaeus. The BaPAD possessed excellent catalytic activity and stability in various organic solvents. Whole Escherichia coli cells harboring intracellular BaPAD exhibited greater tolerances to FA and 4-VG than those of free BaPAD. A highly efficient aqueous-organic biphasic system was established using 1-octanol as the optimal organic phase for whole-cell catalysis. In this system, a very high concentration (1580 mM, 237.3 g/L) of 4-VG was achieved in a 2 L working volume bioreactor, and the molar conversion yield and productivity reached 98.9% and 18.3 g/L/h in 13 h, respectively.

Insights from Mathematical Modelling into Energy Requirement and Process Design of Continuous and Batch Stirred Tank Aerobic Bioreactors

Bioreaction kinetics, oxygen transfer and energy modelling were applied to stirred tank aerobic bioreactors. This was done to investigate how key input design variables influence bioreactor size, feed and wasted substrate, and electrical energy requirements for aeration and cooling, and to compare batch and continuous modes of operation. Oxygen concentration in the liquid is a key input design variable, but its selection is challenging as it can result in design trade-offs. Reducing its value caused a decrease in electrical energy requirement, however this tended to increase the working volume of the bioreactor. The minimum or near-to-minimum total energy requirement for oxygen transfer occurred when operating at the onset of flooding throughout the bioreaction time. For typical KS values, continuous mode of operation required a much smaller bioreactor volume, due to higher operating cell concentration, and this is a major advantage of continuous over batch.

Determination of bacterial intracellular and extracellular biotransformation compounds and biodegradation of kerosene based industrial rolling oils via gas chromatography-mass spectrometry

In the aluminum and steel industry there is no specialized bioremediation of the pure or spent hydrocarbon rolling oils. Hazardous waste management companies remove the spent oils which eventually end up being dumped at local hazardous material dump sites. The lack of an environmentally friendly strategy to reduce the hazardous waste from factories was incentive for this research. The aim was to determine and monitor an indigenous Achromobacter aegrifaciens bacterial biotransformation/biodegradation of Kerosene based rolling oils including the additives: methyl laurate, lauric acid and Shellsol D100. This was done via dehydrogenase assays and Gas Chromatography-Mass Spectrometry. Achromobacter aegrifaciens bacterial biotransformation was also compared to that of an exogenous consortium of Lysinibacillus fusiformis and Pseudomonas synaxantha. Results were analyzed statistically, using SPSS version 24. The mean differences were significant at the 0.05 level for both DHA and GCMS. Further, subterminal oxidation was determined to be the main activation mechanism for the biotransformation. Methylation occurred during rolling oil biotransformation but was more prevalent in biotransformations of the additives, especially methyl laurate. Methylation resulted in less efficient biotransformations compared to subterminal oxidation. This bioremediation strategy can now be further established for larger volume bioreactors as we established that the toxic monoaromatic compounds were successfully degraded at the end of five weeks making this bioremediation strategy a viable alternative to the current dumping by waste companies.