Displaying publications 21 - 40 of 42 in total

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  1. Ariff, A.B., Ooi, T.C., Shamsuddin, Z.H., Halimi, M.S.
    MyJurnal
    The exponential fed-batch cultivation of Bacillus sphaericus UPMB10 in 2 l stirred tank fermenter was performed by feeding the initial batch culture with 14 g l-1 of glycerol according to the algorithm aimed at controlling the specific growth rate (μ) of the bacterium. Very high viable cell count (1.14 x 1010 cfu ml-1), which was four times higher as compared to batch cultivation, was achieved in the fed-batch with a controlled μ at 0.4 h-1. In repeated exponential fed-batch cultivation, consisting of four cycles of harvesting and recharging, a final cell concentration of 1.9 x 1011 cfu ml-1 was obtained at the end of the fourth cycle (46 h). Meanwhile, acetylene reduction of cell samples collected from repeated fed-batch cultivation remained unchanged and was maintained at around 20 nmol C2H2 h-1 ml-1 after prolonged cultivation period, and was comparable to those obtained in batch and exponential fed-batch cultivation. Glycerol could be used as a carbon source for high performance cultivation of B. sphaericus, a nitrogen fixing bacterium, in repeated fed-batch cultivation with high cell yield and cell productivity. The productivity (0.68 g l-1 h-1) for repeated fed-batch cultivation increased about 6 times compared to that obtained in conventional batch cultivation (0.11 g l1 h-1). A innovative method in utilizing glycerol for efficient cultivation of nitrogen fixing bacterium could be beneficial to get more understanding and reference in manipulating the integrated plans for sustainable and profitable biodiesel industry.
    Matched MeSH terms: Batch Cell Culture Techniques
  2. Yamin, S., Shuhaimi, M., Arbakariya, A., Khalilah, A. K., Anas, O., Yazid, A. M., et al.
    MyJurnal
    The use of component from Ganoderma lucidum as prebiotic source is interesting as the G. lucidum itself was known for more than a decade in the traditional Chinese medicine. In this work, Ganoderma lucidum crude polysaccharides (GLCP) and Polysaccharide-fraction number 2 (PF-2) were used as carbon sources in the fermentation with Bifidobacterium sp. The results showed the potential of prebiotic effect of the G. lucidum extract in batch-culture fermentation based on increment in the growth of bacteria used (0.4 – 1.5 log10 CFU/mL) after 18h fermentation. Fermentation was further done using faecal materials as bacterial inocula and bacterial growth changes were examined using real-time PCR. The results showed the ability of GLCP and PF-2 to support the growth of Bifidobacterium genus with 0.3 and 0.7 log10 cells/ml increased, respectively. Interestingly, Lactobacillus which is known as beneficial bacterial genus also showed growth increment with 0.7 and 1 log10 cells/ml increased. The competition for carbon sources thus inhibits the growth of potentially harmful genus, Salmonella (0.3 and 0.5 log10 cells/ml) in comparison to the control.
    Matched MeSH terms: Batch Cell Culture Techniques
  3. Lim JW, Seng CE, Lim PE, Ng SL, Sujari AN
    Bioresour Technol, 2011 Nov;102(21):9876-83.
    PMID: 21890353 DOI: 10.1016/j.biortech.2011.08.014
    The performance of moving bed sequencing batch reactors (MBSBRs) added with 8 % (v/v) of polyurethane (PU) foam cubes as carrier media in nitrogen removal was investigated in treating low COD/N wastewater. The results indicate that MBSBR with 8-mL cubes achieved the highest total nitrogen (TN) removal efficiency of 37% during the aeration period, followed by 31%, 24% and 19 % for MBSBRs with 27-, 64- and 125-mL cubes, respectively. The increased TN removal in MBSBRs was mainly due to simultaneous nitrification and denitrification (SND) process which was verified by batch studies. The relatively lower TN removal in MBSBR with larger PU foam cubes was attributed to the observation that larger PU foam cubes were not fully attached by biomass. Higher concentrations of 8-mL PU foam cubes in batch reactors yielded higher TN removal.
    Matched MeSH terms: Batch Cell Culture Techniques/instrumentation*
  4. Lim JW, Lim PE, Seng CE, Adnan R
    Bioresour Technol, 2013 Feb;129:485-94.
    PMID: 23266850 DOI: 10.1016/j.biortech.2012.11.111
    Moving bed sequencing batch reactors (MBSBRs) packed with 8% (v/v) of 8-, 27- and 64-mL polyurethane (PU) foam cubes, respectively, were investigated for simultaneous 4-chlorophenol (4-CP) and nitrogen removal at increasing 4-CP concentration. When the 4-CP concentration exceeded 300 mg L(-1), the MBSBR with 27-mL foam cubes was observed to outperform the other MBSBRs in removing 4-CP and nitrogen. The reasons were: (1) there were more biomass in inner layer of the 27-mL cubes, compared to that of the 8-mL cubes, which was more shielded from the inhibitory effect of 4-CP and (2) the 27-mL cubes were more mobile than the 64-mL cubes. Although increasing 4-CP concentration to 600 mg L(-1) resulted in incomplete removal of 4-CP in the MBSBRs, results of the batch reactor with 27-mL foam cubes showed that complete 4-CP removal within the REACT period could be achieved by increasing the packing volume to 20%.
    Matched MeSH terms: Batch Cell Culture Techniques/instrumentation*
  5. El Enshasy H, Malik K, Malek RA, Othman NZ, Elsayed EA, Wadaan M
    PMID: 26907552
    Human gastrointestinal microbiota (HGIM) incorporate a large number of microbes from different species. Anaerobic bacteria are the dominant organisms in this microbial consortium and play a crucial role in human health. In addition to their functional role as the main source of many essential metabolites for human health, they are considered as biotherapeutic agents in the regulation of different human metabolites. They are also important in the prevention and in the treatment of different physical and mental diseases. Bifidobacteria are the dominant anaerobic bacteria in HGIM and are widely used in the development of probiotic products for infants, children and adults. To develop bifidobacteria-based bioproducts, therefore, it is necessary to develop a large-scale biomass production platform based on a good understanding of the ideal medium and bioprocessing parameters for their growth and viability. In addition, high cell viability should be maintained during downstream processing and storage of probiotic cell powder or the final formulated product. In this work we review the latest information about the biology, therapeutic activities, cultivation and industrial production of bifidobacteria.
    Matched MeSH terms: Batch Cell Culture Techniques/methods*
  6. Norhafini H, Huong KH, Amirul AA
    Int J Biol Macromol, 2019 Mar 15;125:1024-1032.
    PMID: 30557643 DOI: 10.1016/j.ijbiomac.2018.12.121
    P(3HB-co-4HB) with a high 4HB monomer composition was previously successfully produced using the transformant Cupriavidus malaysiensis USMAA1020 containing an additional copy of the PHA synthase gene. In this study, high PHA density fed-batch cultivation strategies were developed for such 4HB-rich P(3HB-co-4HB). The pulse, constant and mixed feeding strategies resulted in high PHA accumulation, with a PHA content of 74-92 wt% and 4HB monomer composition of 92-99 mol%. The pulse-feed of carbon and nitrogen resulted in higher PHA concentration (30.7 g/L) than carbon alone (22.3 g/L), suggesting that a trace amount of nitrogen is essential to support cell density for PHA accumulation. Constant feeding was found to be a more feasible strategy than mixed feeding, since the latter caused a drastic fluctuation in the C/N ratio, as evidenced by higher biomass formation indicating more carbon flux towards the competitive TCA pathway. A two-times carbon and nitrogen pulse feeding was the most optimal strategy achieving 92 wt% accommodation of the total biomass, with the highest PHA concentration (46 g/L) and yield (Yp/x) of 11.5 g/g. The strategy has kept the C/N at optimal ratio during the active PHA-producing phase. This is the first report of the production of high PHA density for 4HB-rich P(3HB-co-4HB).
    Matched MeSH terms: Batch Cell Culture Techniques/methods*
  7. Zainab-L I, Sudesh K
    J Biotechnol, 2019 Nov 10;305:35-42.
    PMID: 31493421 DOI: 10.1016/j.jbiotec.2019.09.001
    The cost of polyhydroxyalkanoates (PHAs) can be reduced by improving their productivity and recovery. In this study, we attempted to obtain a high cell density culture from a 13 L bioreactor and subsequently improved the recently developed biological recovery process using mealworms to obtain the PHA granules. A cell dry weight of 161 g/L containing 68-70 wt% P(3HB) was obtained. The freeze-dried cells contained a significant amount of mineral salts from the culture medium which reduced the cells' palatability for the mealworms. A simple washing procedure with water was sufficient to remove the residual mineral salts and this improved the cells' consumption by up to 12.5% of the mealworms' body weight. As a result, one kilogram of mealworms consumed 125 g of the washed cells daily and 87.2 g of feacal pellets were recovered, which was almost twice the weight of the unwashed cells. In addition, it also improved the purity of the PHA in the faecal pellets to a value <90% upon washing with water to remove the water-soluble compounds. This study has demonstrated a significant improvement in the production and recovery of PHA. In addition, the resulting mealworms showed a significant increase in protein content up to 79% and a decrease in fat content down to 8.3% of its dry weight.
    Matched MeSH terms: Batch Cell Culture Techniques/methods*
  8. Ng HS, Chai CXY, Chow YH, Loh WLC, Yim HS, Tan JS, et al.
    J Biosci Bioeng, 2018 May;125(5):585-589.
    PMID: 29339003 DOI: 10.1016/j.jbiosc.2017.12.010
    Xylanase enzyme degrades linear polysaccharide β-1,4 xylan and the hemicellulose of the plant cell wall. There is a growing demand in finding a cost-effective alternative for industrial scale production of xylanase with high purity for pharmaceutical applications. In this study, an alcohol/salt aqueous biphasic system (ABS) was adopted to recover xylanase from the Bacillus subtilis fermentation broth. The effects of several ABS parameters such as types and concentrations of alcohols and salts (i.e., sulphate, phosphate, and citrate), amount of crude loading and pH of the system on the recovery of xylanase were investigated. Partition coefficient of xylanase (KE), selectivity (S) and yield (YT) of xylanase in top phase of the ABS were measured. Highest KE (6.58 ± 0.05) and selectivity (4.84 ± 0.33) were recorded in an ABS of pH 8 composed of 26% (w/w) 1-propanol, 18% (w/w) ammonium sulphate. High YT of 71.88% ± 0.15 and a purification fold (PFT) of 5.74 ± 0.33 were recorded with this optimum recovery of xylanase using alcohol/salt ABS. The purity of xylanase recovered was then qualitatively verified with sodium dodecyl sulphate (SDS) gel electrophoresis. The SDS profile revealed the purified xylanase was successfully obtained in the top phase of the one-step 1-propanol/sulphate ABS with a distinct single band.
    Matched MeSH terms: Batch Cell Culture Techniques/methods
  9. Zulkeflee Z, Aris AZ, Shamsuddin ZH, Yusoff MK
    ScientificWorldJournal, 2012;2012:495659.
    PMID: 22997497
    A bioflocculant-producing bacterial strain with highly mucoid and ropy colony morphological characteristics identified as Bacillus spp. UPMB13 was found to be a potential bioflocculant-producing bacterium. The effect of cation dependency, pH tolerance and dosage requirement on flocculating ability of the strain was determined by flocculation assay with kaolin as the suspended particle. The flocculating activity was measured as optical density and by flocs formation. A synergistic effect was observed with the addition of monovalent and divalent cations, namely, Na⁺, Ca²⁺, and Mg²⁺, while Fe²⁺ and Al³⁺ produced inhibiting effects on flocculating activity. Divalent cations were conclusively demonstrated as the best cation source to enhance flocculation. The bioflocculant works in a wide pH range, from 4.0 to 8.0 with significantly different performances (P < 0.05), respectively. It best performs at pH 5.0 and pH 6.0 with flocculating performance of above 90%. A much lower or higher pH would inhibit flocculation. Low dosage requirements were needed for both the cation and bioflocculant, with only an input of 50 mL/L for 0.1% (w/v) CaCl₂ and 5 mL/L for culture broth, respectively. These results are comparable to other bioflocculants produced by various microorganisms with higher dosage requirements.
    Matched MeSH terms: Batch Cell Culture Techniques/methods; Batch Cell Culture Techniques/standards*
  10. Duffy CR, Zhang R, How SE, Lilienkampf A, De Sousa PA, Bradley M
    Biomaterials, 2014 Jul;35(23):5998-6005.
    PMID: 24780167 DOI: 10.1016/j.biomaterials.2014.04.013
    Mesenchymal stems cells (MSCs) are currently the focus of numerous therapeutic approaches in tissue engineering/repair because of their wide multi-lineage potential and their ability to modulate the immune system response following transplantation. Culturing these cells, while maintaining their multipotency in vitro, currently relies on biological substrates such as gelatin, collagen and fibronectin. In addition, harvesting cells from these substrates requires enzymatic or chemical treatment, a process that will remove a multitude of cellular surface proteins, clearly an undesirable process if cells are to be used therapeutically. Herein, we applied a high-throughput 'hydrogel microarray' screening approach to identify thermo-modulatable substrates which can support hES-MP and ADMSC growth, permit gentle reagent free passaging, whilst maintaining multi-lineage potential. In summary, the hydrogel substrate identified, poly(AEtMA-Cl-co-DEAA) cross-linked with MBA, permitted MSCs to be maintained over 10 passages (each time via thermo-modulation), with the cells retaining expression of MSC associated markers and lineage potency. This chemically defined system allowed the passaging and maintenance of cellular phenotype of this clinically important cell type, in the absence of harsh passaging and the need for biological substrates.
    Matched MeSH terms: Batch Cell Culture Techniques/instrumentation*
  11. Seman WM, Bakar SA, Bukhari NA, Gaspar SM, Othman R, Nathan S, et al.
    J Biotechnol, 2014 Aug 20;184:219-28.
    PMID: 24910973 DOI: 10.1016/j.jbiotec.2014.05.034
    A Pichia pastoris transformant carrying the cutinase cDNA of Glomerella cingulata was over-expressed in a 5L bioreactor (2.0L working volume) under fed-batch conditions. Bioreactor experiments rely on varying selected parameters in repeated rounds of optimisation: here these included duration of induction, pH and temperature. Highest cell densities (320gL(-1) wet cell weight) with a cutinase production of 3800mgL(-1) and an activity of 434UmL(-1) were achieved 24h after induction with methanol in basal salt medium (at pH 5 and 28°C). Characterisation of the cutinase showed that it was stable between pH 6 and pH 11, had an optimum pH of 8.0 and retained activity for 30min at 50°C (optimum temperature 25°C).The preferred substrates of G. cingulata cutinase were the medium- to long-chain ρ-nitrophenyl esters of ρ-nitrophenylcaprylate (C8), ρ-nitrophenyllaurate (C12) and ρ-nitrophenylmyristate (C14), with the highest catalytic efficiency, kcat/Km of 7.7±0.7mM(-1)s(-1) for ρ-nitrophenylcaprylate. Microscopic analyses showed that the G. cingulata cutinase was also capable of depolymerising the high molecular weight synthetic polyester, polyethylene terephthalate.
    Matched MeSH terms: Batch Cell Culture Techniques/methods*
  12. Wong YM, Show PL, Wu TY, Leong HY, Ibrahim S, Juan JC
    J Biosci Bioeng, 2019 Feb;127(2):150-159.
    PMID: 30224189 DOI: 10.1016/j.jbiosc.2018.07.012
    Bio-hydrogen production from wastewater using sludge as inoculum is a sustainable approach for energy production. This study investigated the influence of initial pH and temperature on bio-hydrogen production from dairy wastewater using pretreated landfill leachate sludge (LLS) as an inoculum. The maximum yield of 113.2 ± 2.9 mmol H2/g chemical oxygen demand (COD) (12.8 ± 0.3 mmol H2/g carbohydrates) was obtained at initial pH 6 and 37 °C. The main products of volatile fatty acids were acetate and butyrate with the ratio of acetate:butyrate was 0.4. At optimum condition, Gibb's free energy was estimated at -40 kJ/mol, whereas the activation enthalpy and entropy were 65 kJ/mol and 0.128 kJ/mol/l, respectively. These thermodynamic quantities suggest that bio-hydrogen production from dairy wastewater using pretreated LLS as inoculum was effective and efficient. In addition, genomic and bioinformatics analyses were performed in this study.
    Matched MeSH terms: Batch Cell Culture Techniques/methods
  13. Norizan NABM, Halim M, Tan JS, Abbasiliasi S, Mat Sahri M, Othman F, et al.
    Molecules, 2020 Jul 31;25(15).
    PMID: 32752106 DOI: 10.3390/molecules25153516
    Palm kernel cake (PKC) has been largely produced in Malaysia as one of the cheap and abundant agro-waste by-products from the palm oil industry and it contains high fiber (mannan) content. The present study aimed to produce β-mannanase by Bacillus subtilis ATCC11774 via optimization of the medium composition using palm kernel cake as substrate in semi-solid fermentation. The fermentation nutrients such as PKC, peptone, yeast extract, sodium chloride, magnesium sulphate (MgSO2), initial culture pH and temperature were screened using a Plackett-Burman design. The three most significant factors identified, PKC, peptone and NaCl, were further optimized using central composite design (CCD), a response surface methodology (RSM) approach, where yeast extract and MgSO2 were fixed as a constant factor. The maximum β-mannanase activity predicted by CCD under the optimum medium composition of 16.50 g/L PKC, 19.59 g/L peptone, 3.00 g/L yeast extract, 2.72 g/L NaCl and 0.2 g/L MgSO2 was 799 U/mL. The validated β-mannanase activity was 805.12 U/mL, which was close to the predicted β-mannanas activity. As a comparison, commercial media such as nutrient broth, M9 and Luria bertani were used for the production of β-mannanase with activities achieved at 204.16 ± 9.21 U/mL, 50.32 U/mL and 88.90 U/mL, respectively. The optimized PKC fermentation medium was four times higher than nutrient broth. Hence, it could be a potential fermentation substrate for the production of β-mannanase activity by Bacillus subtilis ATCC11774.
    Matched MeSH terms: Batch Cell Culture Techniques
  14. Bajury DM, Rawi MH, Sazali IH, Abdullah A, Sarbini SR
    Int J Food Sci Nutr, 2017 Nov;68(7):821-828.
    PMID: 28393631 DOI: 10.1080/09637486.2017.1309522
    Red seaweed (Kappaphycus alvarezii) cultivated from Sabah (RSS) and Langkawi (RSL) were digested using in vitro mouth, gastric and duodenal model. The digested seaweed then fermented in a pH-controlled batch culture system inoculated with human faeces to mimic the distal colon. Bacterial enumeration were monitored using fluorescent in situ hybridisation, and the fermentation end products, the short chain fatty acids (SCFA), were analysed using HPLC. Both RSS and RSL showed significant increase of Bifidobacterium sp.; from log10 7.96 at 0 h to log10 8.72 at 24 h, and from log10 7.96 at 0 h to log10 8.60 at 24 h, respectively, and shows no significant difference when compared to the Bifidobacterium sp. count at 24 h of inulin fermentation. Both seaweeds also showed significant increase in total SCFA production, particularly acetate and propionate. Overall, this data suggested that K. alvarezii might have the potential as a prebiotic ingredient.
    Matched MeSH terms: Batch Cell Culture Techniques
  15. Chen PW, Cui ZY, Ng HS, Chi-Wei Lan J
    J Biosci Bioeng, 2020 Aug;130(2):195-199.
    PMID: 32370929 DOI: 10.1016/j.jbiosc.2020.03.011
    Ectoine production using inexpensive and renewable biomass resources has attracted great interest among the researchers due to the low yields of ectoine in current fermentation approaches that complicate the large-scale production of ectoine. In this study, ectoine was produced from corn steep liquor (CSL) and soybean hydrolysate (SH) in replacement to yeast extract as the nitrogen sources for the fermentation process. To enhance the bacterial growth and ectoine production, biotin was added to the Halomonas salina fermentation media. In addition, the effects addition of surfactants such as Tween 80 and saponin on the ectoine production were also investigated. Results showed that both the CSL and SH can be used as the nitrogen source substitutes in the fermentation media. Higher amount of ectoine (1781.9 mg L-1) was produced in shake flask culture with SH-containing media as compared to CSL-containing media. A total of 2537.0 mg L-1 of ectoine was produced at pH 7 when SH-containing media was applied in the 2 L batch fermentation. Moreover, highest amount of ectoine (1802.0 mg L-1) was recorded in the SH-containing shake flask culture with addition of 0.2 μm mL-1 biotin. This study demonstrated the efficacy of industrial waste as the nutrient supplement for the fermentation of ectoine production.
    Matched MeSH terms: Batch Cell Culture Techniques
  16. Ong YH, Chua AS, Lee BP, Ngoh GC
    Water Sci Technol, 2013;67(2):340-6.
    PMID: 23168633 DOI: 10.2166/wst.2012.552
    To date, little information is known about the operation of the enhanced biological phosphorus removal (EBPR) process in tropical climates. Along with the global concerns on nutrient pollution and the increasing array of local regulatory requirements, the applicability and compliance accountability of the EBPR process for sewage treatment in tropical climates is being evaluated. A sequencing batch reactor (SBR) inoculated with seed sludge from a conventional activated sludge (CAS) process was successfully acclimatized to EBPR conditions at 28 °C after 13 days' operation. Enrichment of Candidatus Accumulibacter phosphatis in the SBR was confirmed through fluorescence in situ hybridization (FISH). The effects of operational pH and influent C:P ratio on EBPR were then investigated. At pH 7 or pH 8, phosphorus removal rates of the EBPR processes were relatively higher when operated at C:P ratio of 3 than C:P ratio of 10, with 0.019-0.020 and 0.011-0.012 g-P/g-MLVSS•day respectively. One-year operation of the 28 °C EBPR process at C:P ratio of 3 and pH 8 demonstrated stable phosphorus removal rate of 0.020 ± 0.003 g-P/g-MLVSS•day, corresponding to effluent with phosphorus concentration <0.5 mg/L. This study provides the first evidence on good EBPR activity at relatively high temperature, indicating its applicability in a tropical climate.
    Matched MeSH terms: Batch Cell Culture Techniques
  17. Rosman NH, Nor Anuar A, Othman I, Harun H, Sulong Abdul Razak MZ, Elias SH, et al.
    Bioresour Technol, 2013 Feb;129:620-3.
    PMID: 23317554 DOI: 10.1016/j.biortech.2012.12.113
    Aerobic granular sludge (AGS) was successfully cultivated at 27±1 °C and pH 7.0±1 during the treatment of rubber wastewater using a sequential batch reactor system mode with complete cycle time of 3 h. Results showed aerobic granular sludge had an excellent settling ability and exhibited exceptional performance in the organics and nutrients removal from rubber wastewater. Regular, dense and fast settling granule (average diameter, 1.5 mm; settling velocity, 33 m h(-1); and sludge volume index, 22.3 mL g(-1)) were developed in a single reactor. In addition, 96.5% COD removal efficiency was observed in the system at the end of the granulation period, while its ammonia and total nitrogen removal efficiencies were up to 94.7% and 89.4%, respectively. The study demonstrated the capabilities of AGS development in a single, high and slender column type-bioreactor for the treatment of rubber wastewater.
    Matched MeSH terms: Batch Cell Culture Techniques
  18. Venil CK, Zakaria ZA, Ahmad WA
    Acta Biochim. Pol., 2015;62(2):185-90.
    PMID: 25979288 DOI: 10.18388/abp.2014_870
    Flexirubins are the unique type of bacterial pigments produced by the bacteria from the genus Chryseobacterium, which are used in the treatment of chronic skin disease, eczema etc. and may serve as a chemotaxonomic marker. Chryseobacterium artocarpi CECT 8497, an yellowish-orange pigment producing strain was investigated for maximum production of pigment by optimizing medium composition employing response surface methodology (RSM). Culture conditions affecting pigment production were optimized statistically in shake flask experiments. Lactose, l-tryptophan and KH2PO4 were the most significant variables affecting pigment production. Box Behnken design (BBD) and RSM analysis were adopted to investigate the interactions between variables and determine the optimal values for maximum pigment production. Evaluation of the experimental results signified that the optimum conditions for maximum production of pigment (521.64 mg/L) in 50 L bioreactor were lactose 11.25 g/L, l-tryptophan 6 g/L and KH2PO4 650 ppm. Production under optimized conditions increased to 7.23 fold comparing to its production prior to optimization. Results of this study showed that statistical optimization of medium composition and their interaction effects enable short listing of the significant factors influencing maximum pigment production from Chryseobacterium artocarpi CECT 8497. In addition, this is the first report optimizing the process parameters for flexirubin type pigment production from Chryseobacterium artocarpi CECT 8497.
    Matched MeSH terms: Batch Cell Culture Techniques
  19. Shantini K, Yahya AR, Amirul AA
    Appl Biochem Biotechnol, 2015 Jul;176(5):1315-34.
    PMID: 25951779 DOI: 10.1007/s12010-015-1648-5
    Copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] has been the center of attention in the bio-industrial fields, as it possesses superior mechanical properties compared to poly(3-hydroxybutyrate) [P(3HB)]. The usage of oleic acid and 1-pentanol was exploited as the carbon source for the production of P(3HB-co-3HV) copolymer by using a locally isolated strain Cupriavidus sp. USMAA2-4. In this study, the productivity of polyhydroxyalkanoate (PHA) was improved by varying the frequency of feeding in fed-batch culture. The highest productivity (0.48 g/L/h) that represents 200 % increment was obtained by feeding the carbon source and nitrogen source three times and also by considering the oxygen uptake rate (OUR) and oxygen transfer rate (OTR). A significantly higher P(3HB-co-3HV) concentration of 25.7 g/L and PHA content of 66 wt% were obtained. The 3-hydroxyvalerate (3HV) monomer composition obtained was 24 mol% with the growth of 13.3 g/L. The different frequency of feeding carried out has produced a blend copolymer and has broadened the monomer distribution. In addition, increase in number of granules was also observed as the frequency of feeding increases. In general, the most glaring increment in productivity offer advantage for industrial P(3HB-co-3HV) production, and it is crucial in developing cost-effective processes for commercialization.
    Matched MeSH terms: Batch Cell Culture Techniques
  20. Nasrullah A, Bhat AH, Naeem A, Isa MH, Danish M
    Int J Biol Macromol, 2018 Feb;107(Pt B):1792-1799.
    PMID: 29032214 DOI: 10.1016/j.ijbiomac.2017.10.045
    High surface area mesoporous activated carbon-alginate (AC-alginate) beads were successfully synthesized by entrapping activated carbon powder derived from Mangosteen fruit peel into calcium-alginate beads for methylene blue (MB) removal from aqueous solution. The structure and surface characteristics of AC-alginate beads were analyzed using Fourier transform infra-red (FTIR) spectroscopy, scanning electron microscopy (SEM) and surface area analysis (SBET), while thermal properties were tested using thermogravimetric analysis (TGA). The effect of AC-alginate dose, pH of solution, contact time, initial concentration of MB solution and temperature on MB removal was elucidated. The results showed that the maximum adsorption capacity of 230mg/g was achieved for 100mg/L of MB solution at pH 9.5 and temperature 25°C. Furthermore, the adsorption of MB on AC-alginate beads followed well pseudo-second order equation and equilibrium adsorption data were better fitted by the Freundlich isotherm model. The findings reveal the feasibility of AC-alginate beads composite to be used as a potential and low cost adsorbent for removal of cationic dyes.
    Matched MeSH terms: Batch Cell Culture Techniques
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