Displaying publications 61 - 80 of 379 in total

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  1. Fulltext Effects of different fermentation approaches on the microbiological and physicochemical changes during cocoa bean fermentation
    Ganeswari, I., Khairul Bariah, S., Amizi, M.A., Sim, K.Y.
    International Food Research Journal, 2015;22(1):70-76.
    MyJurnal
    The influence of different fermentation methods and turning of cocoa beans on the cocoa bean’s quality was studied. Both shallow box covered with banana leaves (SBBL) and shallow box without banana leaves (SBWL) were used throughout fermentation (120 hours). The initial microbial load for SBBL and SBWL was 5.35±0.18 and 5.19±0.21 log CFU/g before increased to 6.27±0.08 and 6.17±0.03 log CFU/g, respectively at the end of fermentation (120 hours). The titratable acidity of the cocoa beans increased steadily until 72 hours before decreased slightly to 1.34±0.07 (SBBL) and 0.75±0.15 (SBWL) at the latter stage of fermentation. The cocoa beans fermented under SBBL were less acidic than those found in SBWL. Turned cocoa beans produced better quality of cocoa with less acidic compared to the one without turning. Cocoa beans with periodical turning recorded higher percentage of brown beans for both SBBL (73%) and SBWL (69%); percentage of purple beans decreased to about 7-8% for cocoa fermented in respective methods mentioned above. No slaty beans were recorded throughout the study. This study suggests that the use of shallow box with banana leaves can produce cocoa beans with superior quality.
    Matched MeSH terms: Bioreactors
  2. Fulltext Stability study of an exothermic biocatalytic reaction and its application in bioprocess systems
    Mohd. Radzi, M.R., Uzir, M.H.
    Pertanika Journal of Science & Technology, 2009;17(1):-.
    MyJurnal
    Biocatalytic reaction is a type of reaction which uses enzyme or whole-cell as a (bio)-catalyst to achieve a desired conversion, under controlled conditions in a bioreactor. Temperature produces opposed effects on enzyme activity and stability, and is therefore a key variable in any biocatalytic processes. An exothermic biocatalytic reaction, in a continuous-stirred-tank reactor (CSTR), was analyzed where dynamic equations (non-linear differential equations) could be derived from the Michaelis-Menten and Arrhenius equations, by performing mass and energy balances on the reactor. In this work, the effects of the different parameters such as dilution rate, proportional control constant and dimensionless total enzyme concentration, on the stability of the system, were studied. The stability of the reaction could be analyzed, based on the ODE (ordinary differential equation), solved using the numerical technique in MATLAB® and the analytical investigation using Mathematica.® The numerical analysis can be carried out by considering the hase-plane behaviour and bifurcation diagrams of the dynamic equations, while the analytical analysis using Mathematica® can be undertaken by evaluating the eigenvalues of the system. In order to model the operational stability of biocatalysts, modulation factors need to be considered so that a proper design of bioreactors can be done. Temperature, as a key variable in such bioprocess systems, can be conveniently optimized through the use of appropriate models.
    Matched MeSH terms: Bioreactors
  3. Performance of pilot scale anaerobic biofilm digester (ABD) for the treatment of leachate from a municipal waste transfer station
    Arij Y, Fatihah S, Rakmi AR
    Bioresour Technol, 2018 Jul;260:213-220.
    PMID: 29626780 DOI: 10.1016/j.biortech.2018.03.131
    The anaerobic treatment of leachate from a municipal waste transfer station in Malaysia was tested using a pilot scale anaerobic biofilm digester system that was operated under HRT sequence of 30-day, 25-day, 20-day and 10-day for 163 days under mesophilic conditions. Despite the leachate's complex characteristics, the system showed great performance given its maximum COD, BOD5 and total phosphorus removal efficiencies of 98 ± 1%, 99 ± 1% and 92 ± 9% respectively. The system was stable throughout its operation and showed optimal average values for the monitored parameters such as pH (7.53 ± 0.14), total VFA (79 ± 66 mg HOAc/L), alkalinity (10,919 ± 1556 mg CaCO3/L) and a non-toxic value for accumulated ammonia (960 ± 106 mg NH3-N/L). Measurement of the average daily biogas production yielded a value of 25 ± 1 m3/day throughout the system's operation with a composition of 57 ± 12% methane and 26 ± 6% carbon dioxide.
    Matched MeSH terms: Bioreactors
  4. Fulltext Fermentation of Morinda citrifolia extract by Saccharomyces cerevisiae as affected by substrate concentration, inoculum size, temperature and fermentation time
    Nur Hafiza, Z., Maskat, M.Y., Liew, S.L., Mamot, S.
    International Food Research Journal, 2013;20(4):1889-1894.
    MyJurnal
    A study was carried out to observe the fermentation process for noni (Morinda citrifolia L.) extract by Saccharomyces cerevisiae. The experiment was based on a central composite rotatable design (CCRD) employing 5 center points with augmented axial and factorial points resulting in 30 runs. The M. citrifolia extract was fermented with different combination of substrate concentration (40, 50, 60, 70 and 80%) (w/v), inoculum size (0, 1.5, 3, 4.5 and 6%) (v/v), temperature (30, 33.5, 37, 40.5 and 44oC) and fermentation time (0, 1.5, 3, 4.5 and 6 days). Five physico-chemical characteristics which include pH, titratable acidity, turbidity, total soluble solids and total polyphenol content were measured. Results showed that all the responses could be well represented using statistical models. For pH, only fermentation time was found to be not significant, while for titratable acidity and total polyphenol content, the effects of substrate concentration and fermentation time were significant. The effects of inoculum size and temperature level were found to be significant for turbidity. For total soluble solids, only the effect of substrate concentration and inoculum size were found to be significant.
    Matched MeSH terms: Bioreactors
  5. Comprehensive exergoeconomic analysis of a municipal solid waste digestion plant equipped with a biogas genset
    Aghbashlo M, Tabatabaei M, Soltanian S, Ghanavati H, Dadak A
    Waste Manag, 2019 Mar 15;87:485-498.
    PMID: 31109549 DOI: 10.1016/j.wasman.2019.02.029
    A comprehensive exergoeconomic performance analysis of a municipal solid waste digestion plant integrated with a biogas genset was conducted throughout this study in order to highlight its bottlenecks for further improvements. Exergoeconomic performance parameters of each component of the plant were determined by solving exergy and cost balance equations based on Specific Exergy Costing (SPECO) approach. The analysis was conducted to reveal the cost structure of the plant based on actual operating information and economic data. The exergy unitary cost of two main products of the plant, i.e., bioelectricity and biofertilizer were determined at 26.27 and 2.27 USD/GJ, respectively. The genset showed the highest overall cost rate (101.27 USD/h) followed by digester (68.41 USD/h). Furthermore, the net bioelectricity amounted to 67.81% of the overall cost rate of the products, while this value was 32.19% for both liquid and dewatered digestates. According to the results obtained, efforts should mainly focus on enhancing the efficiency of the genset in order to boost the overall performance of the system exergoeconomically. In addition, minimizing the investment-related cost of the digester could also substantially enhance the exergoeconomic performance of the plant.
    Matched MeSH terms: Bioreactors
  6. Enzymatic pretreatment to enhance anaerobic bioconversion of high strength wastewater to biogas: A review
    Liew YX, Chan YJ, Manickam S, Chong MF, Chong S, Tiong TJ, et al.
    Sci Total Environ, 2020 Apr 15;713:136373.
    PMID: 31954239 DOI: 10.1016/j.scitotenv.2019.136373
    Oil and grease, carbohydrate, protein, and lignin are the main constituents of high strength wastewaters such as dairy wastewater, cheese whey wastewater, distillery wastewater, pulp and paper mill wastewater, and slaughterhouse wastewaters. These constituents have contributed to various operational problems faced by the high-rate anaerobic bioreactor (HRAB). During the hydrolysis stage of anaerobic digestion (AD), these constituents can be hydrolyzed. Since hydrolysis is known to be the rate-limiting step of AD, the overall AD can be enhanced by improving the hydrolysis stage. This can be done by introducing pretreatment that targets the degradation of these constituents. This review mainly focuses on the biological pretreatment on various high-strength wastewaters by using different types of enzymes namely lipase, amylase, protease, and ligninolytic enzymes which are responsible for catalyzing the degradation of oil and grease, carbohydrate, protein, and lignin respectively. This review provides a summary of enzymatic systems involved in enhancing the hydrolysis stage and consequently improve biogas production. The results show that the use of enzymes improves the biogas production in the range of 7 to 76%. Though these improvements are highly dependent on the operating conditions of pretreatment and the types of substrates. Therefore, the critical parameters that would affect the effectiveness of pretreatment are also discussed. This review paper will serve as a useful piece of information to those industries that face difficulties in treating their high-strength wastewaters for the appropriate process, equipment selection, and design of an anaerobic enzymatic system. However, more intensive studies on the optimum operating conditions of pretreatment in a larger-scale and synergistic effects between enzymes are necessary to make the enzymatic pretreatment economically feasible.
    Matched MeSH terms: Bioreactors
  7. Recent development of unconventional aqueous biphasic system: characteristics, mechanisms and applications
    Kee PE, Ng TC, Lan JC, Ng HS
    Crit Rev Biotechnol, 2020 Jun;40(4):555-569.
    PMID: 32283954 DOI: 10.1080/07388551.2020.1747388
    Aqueous biphasic system (ABS) is widely used in the recovery, extraction, purification and separation of proteins, enzymes, nucleic acids and antibodies. The ABS with high water content and low interfacial tension offers a biocompatible environment for the recovery of labile biomolecules. Process integration can be achieved using ABS by incorporating multiple-steps of purification, concentration and purification of biomolecules in a single-step operation which often results in high product recovery yield and purity. Conventional ABS is usually formed by aqueous solutions of two polymers or a polymer and a salt above a critical concentration. The high viscosity of polymer-based ABS causes slow phase separation and hinders the mass transfer of biomolecules, whereas polymer/salt ABS is characterized by high ionic strength resulting in the loss of bioactivity of recovered biomolecules. These limitations have encouraged the development of novel ABS which is more cost-effective for various biotechnological applications. This review discusses the characteristics and mechanisms of several types of emerging unconventional ABS using phase-forming components such as hyperbranched polymers, special salts, surfactants, magnetic fields, the addition of nanoparticles and incorporation of various solvent. Moreover, several novel applications of ABS for different separation purposes such as microfluidic-based ABS, ABS bioreactors, application of ABS as an analytical tool, and ABS micropatterning are discussed in this review. In the last section of this review, a comprehensive summary of process integration using ABS for extractive fermentations, bioconversion, crystallization and precipitation is also supplemented for the comprehensive review of various types and applications of ABS in recent years.
    Matched MeSH terms: Bioreactors
  8. Fulltext Patterned Membrane in an Energy-Efficient Tilted Panel Filtration System for Fouling Control in Activated Sludge Filtration
    Osman A, Mat Nawi NI, Samsuri S, Bilad MR, Shamsuddin N, Khan AL, et al.
    Polymers (Basel), 2020 Feb 12;12(2).
    PMID: 32059397 DOI: 10.3390/polym12020432
    A membrane bioreactor enhances the overall biological performance of a conventional activated sludge system for wastewater treatment by producing high-quality effluent suitable for reuse. However, membrane fouling hinders the widespread application of membrane bioreactors by reducing the hydraulic performance, shortening membrane lifespan, and increasing the operational costs for membrane fouling management. This study assesses the combined effect of membrane surface corrugation and a tilted panel in enhancing the impact of air bubbling for membrane fouling control in activated sludge filtration, applicable for membrane bioreactors. The filterability performance of such a system was further tested under variable parameters: Filtration cycle, aeration rate, and intermittent aeration. Results show that a combination of surface corrugation and panel tilting enhances the impact of aeration and leads to 87% permeance increment. The results of the parametric study shows that the highest permeance was achieved under short filtration-relaxation cycle of 5 min, high aeration rate of 1.5 L/min, and short switching period of 2.5 min, to yield the permeances of 465 ± 18, 447 ± 2, and 369 ± 9 L/(m2h bar), respectively. The high permeances lead to higher operational flux that helps to lower the membrane area as well as energy consumption. Initial estimation of the fully aerated system yields the energy input of 0.152 kWh/m3, much lower than data from the full-scale references of <0.4 kWh/m3. Further energy savings and a lower system footprint can still be achieved by applying the two-sided panel with a switching system, which will be addressed in the future.
    Matched MeSH terms: Bioreactors
  9. Tropical-based EBPR process: The long-term stability, microbial community and its response towards temperature stress
    Poh PK, Ong YH, Arumugam K, Nittami T, Yeoh HK, Bessarab I, et al.
    Water Environ Res, 2021 Nov;93(11):2598-2608.
    PMID: 34260796 DOI: 10.1002/wer.1611
    Temperature is known to influence the operational efficiency of enhanced biological phosphorus removal (EBPR) systems. This study investigated the impact of thermal stress above 30°C on the properties of an EBPR community established with tropical inoculum. The results confirmed the stability of the 30°C EBPR system with high P-removal efficiency over 210 days. Accumulibacter was abundant in the community. When the EBPR sludge was subjected to a sudden temperature increase to 35°C under multiple cycles of anaerobic-aerobic phases, each lasting 4 h, high P-removal was maintained over 2 days, before gradually failing when the Competibacter appeared to outcompete Accumulibacter. These data suggested that the EBPR capacity is robust when subjected to occasional thermal stress. However, it could not be maintained even for a short time under temperature stress at 40°C. Thus, the threshold temperature for tropical EBPR failure is between 35°C and 40°C. PRACTITIONER POINTS: EBPR was stably maintained at 30°C with Accumulibacter being dominant. Good EBPR activities persisted for a short period at 35°C. EBPR was deteriorated at 40°C. The threshold temperature for tropical EBPR failure is between 35°C and 40°C.
    Matched MeSH terms: Bioreactors
  10. Effects of wastewater type on stability and operating conditions control strategy in relation to the formation of aerobic granular sludge - a review
    Hamiruddin NA, Awang NA, Mohd Shahpudin SN, Zaidi NS, Said MAM, Chaplot B, et al.
    Water Sci Technol, 2021 Nov;84(9):2113-2130.
    PMID: 34810301 DOI: 10.2166/wst.2021.415
    Currently, research trends on aerobic granular sludge (AGS) have integrated the operating conditions of extracellular polymeric substances (EPS) towards the stability of AGS systems in various types of wastewater with different physical and biochemical characteristics. More attention is given to the stability of the AGS system for real site applications. Although recent studies have reported comprehensively the mechanism of AGS formation and stability in relation to other intermolecular interactions such as microbial distribution, shock loading and toxicity, standard operating condition control strategies for different types of wastewater have not yet been discussed. Thus, the dimensional multi-layer structural model of AGS is discussed comprehensively in the first part of this review paper, focusing on diameter size, thickness variability of each layer and diffusion factor. This can assist in facilitating the interrelation between disposition and stability of AGS structure to correspond to the changes in wastewater types, which is the main objective and novelty of this review.
    Matched MeSH terms: Bioreactors
  11. Effect of famine-phase reduced aeration on polyhydroxyalkanoate accumulation in aerobic granules
    Vjayan T, Vadivelu VM
    Bioresour Technol, 2017 Dec;245(Pt A):970-976.
    PMID: 28946198 DOI: 10.1016/j.biortech.2017.09.038
    The effects of variable aeration in the famine period on polyhydroxyalkanoate (PHA) accumulation in aerobic granules were investigated. Results showed that regardless of the aeration rates used during famine period, all aerobic granules achieved a similar chemical oxygen demand removal and PHA content. The decrease in famine-period aeration rates accelerated the maximum PHA accumulation together with increase in granular size and settling ability. The PHA-accumulating microorganisms were found to have shifted closer to the surface of the granules when the aeration rate was reduced. Moreover, PHA compositional changes occurred, where the hydroxyvalerate content had increased with the reduction in aeration rate. Ultimately, the results indicate that the requirement of aeration for PHA accumulation in aerobic granules is highly insignificant in the famine phase. PHA production in aerobic granules under zero aeration in the famine period may result in an energy input reduction of up to 74%.
    Matched MeSH terms: Bioreactors
  12. Fulltext A new source of Saccharomyces cerevisiae as a leavening agent in bread making
    Noroul Asyikeen, Z., Ma’aruf, A.G., Sahilah, A.M., Mohd. Khan, A., Wan Aida, W.M.
    International Food Research Journal, 2013;20(2):967-973.
    MyJurnal
    Megabiodiversity of Malaysian’s flora and fauna which include microorganism could be conserved and served as alternative source indigenous yeast, the leavening agent of commercial bread making. This study was conducted in attempt to exploit the potential of Saccharomyces cerevisiae strains isolated from 30 different local fruits and plant parts as a leavening agent in bread making. The enrichment was carried out by fermenting the plant samples in medium containing Grape Must at 25°C for 10 days following by isolation of tentative yeasts at 30°C for 3 to 5 days. 20 out of 30 samples tested showed the presence of yeasts was then selected for identification of S. cerevisiae strains through biochemical and physiological tests. Of the 20 yeast strains examined, 13 strains were identified as S. cerevisiae and potentially used as leavening agent in bread making where 5 strains namely SN3, SMK9, SDB10, SRB11 and SS12 showed better fermentative performance compared to commercial strains. Thus, indicated that the local fruits and plant parts could be the potential source of indigenous S. cerevisiae strains for leavening agent in bread making.
    Matched MeSH terms: Bioreactors
  13. Self-flocculation of enriched mixed microalgae culture in a sequencing batch reactor
    Gobi S, Gobi K, Lee KT, Vadivelu V
    Environ Sci Pollut Res Int, 2021 Jun;28(21):26595-26605.
    PMID: 33484460 DOI: 10.1007/s11356-021-12615-4
    Microalgae-based biodiesel has gained widespread interest as an alternative energy source. Low-cost microalgae harvesting technologies are important for economically feasible biodiesel production. This study investigated, for the first time, the impact of adaptation period and height to diameter (H/D) ratio of a reactor on the growth and self-flocculation of microalgae, without the addition of bacteria. Six reactors were grouped into three sets of experiments, and each reactor was operated for 30 days at similar operating conditions (volume exchange ratio = 25% and settling time = 30 min). In set 1, two 8-L reactors, H5a (H/D ratio: 5) and H8a (H/D ratio: 8), were operated under batch operation. In set 2, reactors H5b and H8b were operated as sequential batch reactors (SBRs) without an adaptation period. In set 3, the reactors H5c and H8c were operated as SBRs with an adaptation period. The findings showed a threefold improvement in biomass productivity for the higher H/D ratio (H8c) and a reduction in biomass loss for microalgae. The H8c reactor exhibited 95% settling efficiency within 5 days, in comparison to 30 days for the H5c reactor. This study demonstrated that a higher H/D ratio and the introduction of an adaptation period in SBR operation positively influences growth and self-flocculation of enriched mixed microalgae culture.
    Matched MeSH terms: Bioreactors
  14. Production of Trichoderma harzianum K179 bioagent for maize diseases control: complete laboratory stage bioprocess development
    Mitrović I, Vučurović D, Al-Ani LKT, Mitrović B, Bajić B, Dodić S, et al.
    J Appl Microbiol, 2023 Jun 01;134(6).
    PMID: 37279914 DOI: 10.1093/jambio/lxad115
    AIMS: In order to be competitive on the market, the production of biopreparations needs to be optimized, modelled, and assessed in the early stages of its development. The aim of this paper was to optimize medium for the production of Trichoderma harzianum K179 biocontrol agent, to analyze its kinetics at enlarged laboratory scale and finally economic analysis of the production of this high-value product through simulation modelling.

    METHODS AND RESULTS: The results showed that the bioprocess of T. harzianum K179 bioagent production in a laboratory bioreactor on the medium with optimal composition (dextrose 10 g l-1, soy flour 6.87 g l-1, K2HPO4 1.51 g l-1, KCl 0.5 g l-1, and MgSO4 × 7H2O 0.5 g l-1), at stirring speed of 1.75 × g and aeration intensity of 1.5 vvm, can be shortened from 96 to 36 h. The results of bioprocess economic analysis showed that with a 25-year project lifetime and an investment payback time of 7.58 years, this project represents an economically viable system.

    CONCLUSIONS: Complete analysis of the bioprocess of T. harzianum K179 biocontrol agent production showed that the biologically produced preparation can be competitive on the market with synthetic preparations.

    Matched MeSH terms: Bioreactors
  15. Investigating the crude oil biodegradation performance in bioreactor by using a consortium of symbiotic bacteria
    Chuah LF, Nawaz A, Dailin DJ, Oloruntobi O, Habila MA, Tong WY, et al.
    Chemosphere, 2023 Oct;337:139293.
    PMID: 37369285 DOI: 10.1016/j.chemosphere.2023.139293
    Crude oil pollution is one of the most serious environmental issues today, and the clean-up procedure is perhaps the most difficult. Within one to three weeks, the vast majority of oil bacteria may degrade approximately 60% of the crude oil, leaving approximately 40% intact. The by-product metabolites produced during the breakdown of oil are essentially organic molecules in nature. These metabolites inhibit its enzymes, preventing the oil bacteria from further degrading the oil. By combining a variety of different oils with heterotrophic bacteria in a bioreactor, the rate of crude oil biodegradation was accelerated. In this study, two strains of oil-resistant, heterotrophic bacteria (OG1 and OG2-Erythrobacter citreus) and a bacterium that uses hydrocarbons (AR3-Pseudomonas pseudoalcaligenes) were used. Gas chromatography-mass spectroscopy was used to investigate the effectiveness of this consortium of symbiotic bacteria in the biodegradation of crude oil. According to gravimetric and gas chromatography analyses, the consortium bacteria digested 69.6% of the crude oil in the bioreactor, while the AR3 single strain was only able to destroy 61.9% of it. Under the same experimental conditions, consortium bacteria degraded approximately 84550.851 ppb (96.3%) of 16 aliphatic hydrocarbons and 9333.178 ppb (70.5%) of 16 aromatic hydrocarbons in the bioreactor. It may be inferred that the novel consortium of symbiotic bacteria accelerated the biodegradation process and had great potential for use in increasing the bioremediation of hydrocarbon-contaminated locations.
    Matched MeSH terms: Bioreactors
  16. Insights into biofilm development on polyhydroxyalkanoate biofilm carrier for anoxic azo dye decolourization of acid orange 7
    Chang JY, Syauqi TA, Sudesh K, Ng SL
    Bioresour Technol, 2024 Feb;393:130054.
    PMID: 37995876 DOI: 10.1016/j.biortech.2023.130054
    Polyhydroxyalkanoates (PHAs) are promising alternatives to non-degradable polymers in various applications. This study explored the use of biologically recovered PHA as a biofilm carrier in a moving bed biofilm reactor for acid orange 7 treatment. The PHA was comprised of 86 ± 1 mol% of 3-hydroxybutyrate and 14 ± 1 mol% of 3-hydroxyhexanoate and was melt-fused at 140 °C into pellets. The net positive surface charge of the PHA biocarrier facilitated attachment of negatively charged activated sludge, promoting biofilm formation. A 236-µm mature biofilm developed after 26 days. The high polysaccharides-to-protein ratio (>1) in the biofilm's extracellular polymeric substances indicated a stable biofilm structure. Four main microbial strains in the biofilm were identified as Leclercia adecarboxylata, Leuconostoc citreum, Bacillus cereus, and Rhodotorula mucilaginosa, all of which exhibited decolourization abilities. In conclusion, PHA holds promise as an effective biocarrier for biofilm development, offering a sustainable alternative in wastewater treatment applications.
    Matched MeSH terms: Bioreactors
  17. Optimizing neural network algorithms for submerged membrane bioreactor: A comparative study of OVAT and RSM hyperparameter optimization techniques
    Ibrahim S, Abdul Wahab N
    Water Sci Technol, 2024 Apr;89(7):1701-1724.
    PMID: 38619898 DOI: 10.2166/wst.2024.099
    Hyperparameter tuning is an important process to maximize the performance of any neural network model. This present study proposed the factorial design of experiment for screening and response surface methodology to optimize the hyperparameter of two artificial neural network algorithms. Feed-forward neural network (FFNN) and radial basis function neural network (RBFNN) are applied to predict the permeate flux of palm oil mill effluent. Permeate pump and transmembrane pressure of the submerge membrane bioreactor system are the input variables. Six hyperparameters of the FFNN model including four numerical factors (neuron numbers, learning rate, momentum, and epoch numbers) and two categorical factors (training and activation function) are used in hyperparameter optimization. RBFNN includes two numerical factors such as a number of neurons and spreads. The conventional method (one-variable-at-a-time) is compared in terms of optimization processing time and the accuracy of the model. The result indicates that the optimal hyperparameters obtained by the proposed approach produce good accuracy with a smaller generalization error. The simulation results show an improvement of more than 65% of training performance, with less repetition and processing time. This proposed methodology can be utilized for any type of neural network application to find the optimum levels of different parameters.
    Matched MeSH terms: Bioreactors
  18. Fulltext Biohydrogen Production from Hydrolysates of Selected Tropical Biomass Wastes with Clostridium Butyricum
    Dan Jiang, Fang Z, Chin SX, Tian XF, Su TC
    Sci Rep, 2016 06 02;6:27205.
    PMID: 27251222 DOI: 10.1038/srep27205
    Biohydrogen production has received widespread attention from researchers in industry and academic fields. Response surface methodology (RSM) was applied to evaluate the effects of several key variables in anaerobic fermentation of glucose with Clostridium butyrium, and achieved the highest production rate and yield of hydrogen. Highest H2 yield of 2.02 mol H2/mol-glucose was achieved from 24 h bottle fermentation of glucose at 35 °C, while the composition of medium was (g/L): 15.66 glucose, 6.04 yeast extract, 4 tryptone, 3 K2HPO4, 3 KH2PO4, 0.05 L-cysteine, 0.05 MgSO4·7H2O, 0.1 MnSO4·H2O and 0.3 FeSO4·7H2O, which was very different from that for cell growth. Sugarcane bagasse and Jatropha hulls were selected as typical tropical biomass wastes to produce sugars via a two-step acid hydrolysis for hydrogen production. Under the optimized fermentation conditions, H2 yield (mol H2/mol-total reducing sugar) was 2.15 for glucose, 2.06 for bagasse hydrolysate and 1.95 for Jatropha hull hydrolysate in a 3L fermenter for 24 h at 35 °C, with H2 purity of 49.7-64.34%. The results provide useful information and basic data for practical use of tropical plant wastes to produce hydrogen.
    Matched MeSH terms: Bioreactors/microbiology
  19. Applicability of fluidized bed reactor in recalcitrant compound degradation through advanced oxidation processes: a review
    Tisa F, Abdul Raman AA, Wan Daud WMA
    J Environ Manage, 2014 Dec 15;146:260-275.
    PMID: 25190594 DOI: 10.1016/j.jenvman.2014.07.032
    Treatment of industrial waste water (e.g. textile waste water, phenol waste water, pharmaceutical etc) faces limitation in conventional treatment procedures. Advanced oxidation processes (AOPs) do not suffer from the limits of conventional treatment processes and consequently degrade toxic pollutants more efficiently. Complexity is faced in eradicating the restrictions of AOPs such as sludge formation, toxic intermediates formation and high requirement for oxidants. Increased mass-transfer in AOPs is an alternate solution to this problem. AOPs combined with Fluidized bed reactor (FBR) can be a potential choice compared to fixed bed or moving bed reactor, as AOP catalysts life-span last for only maximum of 5-10 cycles. Hence, FBR-AOPs require lesser operational and maintenance cost by reducing material resources. The time required for AOP can be minimized using FBR and also treatable working volume can be increased. FBR-AOP can process from 1 to 10 L of volume which is 10 times more than simple batch reaction. The mass transfer is higher thus the reaction time is lesser. For having increased mass transfer sludge production can be successfully avoided. The review study suggests that, optimum particle size, catalyst to reactor volume ratio, catalyst diameter and liquid or gas velocity is required for efficient FBR-AOP systems. However, FBR-AOPs are still under lab-scale investigation and for industrial application cost study is needed. Cost of FBR-AOPs highly depends on energy density needed and the mechanism of degradation of the pollutant. The cost of waste water treatment containing azo dyes was found to be US$ 50 to US$ 500 per 1000 gallons where, the cost for treating phenol water was US$ 50 to US$ 800 per 1000 gallons. The analysis for FBR-AOP costs has been found to depend on the targeted pollutant, degradation mechanism (zero order, 1st order and 2nd order) and energy consumptions by the AOPs.
    Matched MeSH terms: Bioreactors*
  20. Treatment of agro based industrial wastewater in sequencing batch reactor: performance evaluation and growth kinetics of aerobic biomass
    Lim JX, Vadivelu VM
    J Environ Manage, 2014 Dec 15;146:217-225.
    PMID: 25173730 DOI: 10.1016/j.jenvman.2014.07.023
    A sequencing batch reactor (SBR) with a working volume of 8 L and an exchange ratio of 25% was used to enrich biomass for the treatment of the anaerobically treated low pH palm oil mill effluent (POME). The influent concentration was stepwise increased from 5000 ± 500 mg COD/L to 11,500 ± 500 mg COD/L. The performance of the reactor was monitored at different organic loading rates (OLRs). It was found that approximately 90% of the COD content of the POME wastewater was successfully removed regardless of the OLR applied to the SBR. Cycle studies of the SBR show that the oxygen uptake by the biomass while there is no COD reduction may be due to the oxidation of the storage product by the biomass. Further, the growth kinetic parameters of the biomass were determined in batch experiments using respirometer. The maximum specific growth rate (μmax) was estimated to be 1.143 day(-1) while the half saturation constant (Ks) with respect to COD was determined to be 0.429 g COD/L. The decay coefficient (bD) and biomass yield (Y) were found to be 0.131 day(-1) and 0.272 mg biomass/mg COD consumed, respectively.
    Matched MeSH terms: Bioreactors*
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