https://vital.seals.ac.za/vital/access/manager/Index ${session.getAttribute("locale")} 5 https://vital.seals.ac.za/vital/access/manager/Repository/vital:3913 Wed 12 May 2021 23:37:14 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3925 Wed 12 May 2021 23:30:20 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3947 Wed 12 May 2021 23:14:43 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4071 Wed 12 May 2021 22:26:49 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4009 50%). Thus, it can be concluded that the cavities of apoferitin and GroEL acted as nanobiofactories for the synthesis and confinement of the size and shape of nanoparticles. Furthermore, the interior of these proteins provided a shielding effect for these nanoparticles and thus reduced/prevented their possible neurotoxic effect and confirmed safety in their method of production and application. The findings from this study would prove beneficial in the application of these nanoparticles as a potential drug/drug delivery vehicle for the prevention, treatment/management of diseases associated with these enzymes/proteins.]]> Wed 12 May 2021 22:22:09 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4065 Wed 12 May 2021 20:35:39 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4042 Wed 12 May 2021 20:35:17 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4070 ethyl acetate > chloroform. The DPPH free radical scavenging activity of the methanol plant extracts increased in the order Brachylaena elliptica > Plumbago auriculata > Grewia robusta > Azima tetracantha. Methanol extracts on the TLC plate sprayed with Fe³⁺-2,4,6-Tri-2-pyridyl-s-triazine (TPTZ) showed that the compounds present in the extracts react differently to ferric ion, with most compounds unable to reduce ferric ion. Furthermore the methanol extracts were able to exhibit reduction potentials vs. Ag/AgCl at low concentrations. The compounds in the extracts were shown to be phenolic acids and flavonoid glycosides.]]> Wed 12 May 2021 20:35:11 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4122 Wed 12 May 2021 20:31:39 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4110 Wed 12 May 2021 20:25:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3883 Wed 12 May 2021 20:23:57 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3951 Wed 12 May 2021 20:17:22 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3908 Wed 12 May 2021 19:53:06 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4043 Wed 12 May 2021 19:40:59 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4007 Wed 12 May 2021 19:29:13 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3933 Wed 12 May 2021 19:16:50 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3956 Wed 12 May 2021 19:06:36 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4157 Wed 12 May 2021 18:59:18 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4103 Wed 12 May 2021 18:47:03 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3943 Wed 12 May 2021 18:23:35 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:37859 Wed 12 May 2021 18:21:20 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4121 Wed 12 May 2021 18:17:29 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3955 Wed 12 May 2021 18:14:36 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4076 10,000 mg/I), numerous metals and high concentrations of those metals (> 20 mg/l of platinum group metals) in the wastewater are the main challenges for biological removal of nitrogenous compounds from PMR wastewater. Nitrogenous compounds such as NH₄⁺-N and N0₃-N are strong metal ligands, which make it difficult to recover metals from the wastewater. Therefore, a bioprocess was developed for removal of nitrogenous compounds from carefully simulated PMR wastewater. A preliminary investigation of metal wastewater was carried out to determine its composition and physico-chemical properties, the ability to nitrify and denitrify under different pH conditions and denitrification with different carbon Source compounds and amounts. Even at pH 4, nitrification could be carried out. A suitable hydraulic retention time was found to be 72 hours. There was no significant difference between sodium acetate and sodium lactate as carbon sources for denitrification. Based on these results, a reactor comparison study was carried out using simulated PMR wastewater in three types of reactors: continuously stirred tank reactor (CSTR), packed-bed reactor (PBR) and airlift suspension reactor (ALSR). These reactors were fed with 30 mg/l of Rh bound in an NH₄⁺ based compound (Claus salt: pentaaminechlororhodium (III) dichloride). Total nitrogen removal efficiencies of > 68 % , > 79 % and > 45 % were obtained in the CSTR, PBR and ALSR, respectively. Serially connected CSTR-PBR and PBR-CSTR reactor configurations were then studied to determine the best configuration for maximum removal of nitrogenous compounds from the wastewater. The PBR-CSTR configuration gave consistent biomass retention and automatic pH control in the CSTR. Ammonium removal efficiencies > 95 % were achieved in both reactors. As poor nitrate removal was observed a toxicity study was carried out using respirometry and the half saturation inhibition coefficients for Pt, Pd, Rh and Ru were found to be 15.81, 25.00, 33.34 and 39.25 mg/l, respectively. A mathematical model was developed to describe the nitrogen removal in PMR wastewater using activated sludge model number 1 (ASMl), two step nitrification and metal toxicity. An operational protocol was developed based on the literature review, experimental work and simulation results. The optimum reactor configuration under the set conditions (20 mg/I of Rh and < 100 mg/I of NH₄⁺-N) was found to be PBR-CSTR-PBR process, which achieved overall NH₄⁺-N and N0₃⁻-N removal efficiencies of > 90 % and 95 %, respectively. Finally, a rudimentary microbial characterisation was carried out on subsamples from the CSTR and PBRsecondary. It was found that the CSTR biomass consisted of both rods and cocci while PBRsecondary consisted of rods only. Based on these experimental works, further research needs and recommendations were made for optimisation of the developed bioprocess for removal of nitrogenous compounds from PMR wastewater.]]> Wed 12 May 2021 18:01:58 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3932 Wed 12 May 2021 17:27:51 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3899 Wed 12 May 2021 17:09:38 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4134 Wed 12 May 2021 17:09:04 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4099 Wed 12 May 2021 16:48:48 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4022 Wed 12 May 2021 16:47:55 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4081 Wed 12 May 2021 16:44:06 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3892 Wed 12 May 2021 16:34:03 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3926 Wed 12 May 2021 16:16:44 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3948 Wed 12 May 2021 16:14:46 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3946 Wed 12 May 2021 16:14:37 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:26595 Wed 12 May 2021 16:05:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3906 Wed 12 May 2021 16:01:01 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4115 Wed 12 May 2021 15:59:57 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3940 90% of the algae population. Under batch operation the population dynamic shifted; Chlorella outcompeted Micractinium possibly due to nutrient depletion and selective grazing pressures caused by proliferation of Daphnia. Higher species diversity was observed during batch mode as slower growing algae were able to establish in the HRAP. Nutrient removal efficiency and biomass productivity was higher in continuous mode, however lower nutrient levels were obtained in batch operation. HMTBA did not significantly affect growth rate, however treatment with 10 mg.L-1 resulted in slightly increased growth rate in Micractinium and increased final biomass concentrations in Chlorella, Micractinium and Spirulina (although this was not statistically significant for Micractinium and Spirulina), which are known mixotrophic species. Algae treated with Cu-HMTBA, showed reduced final biomass concentration with 10 mg.L-1, caused by Cu toxicity. Biochemical composition of the algae was species-specific and differed through the growth cycle, with high protein observed during early growth and high carbohydrate during late growth/early stationary phase. Additionally, 0.1 mg.L-1 HMTBA and Cu-HMTBA significantly reduced protein content in Chlorella, Micractinium, Scenedesmus and Pediastrum. In conclusion, operation of the HRAP in continuous culture provided suitable wastewater treatment with high productivity of an ideal species, Micractinium, for use in animal feed supplementation. This species had 40% protein content during growth (higher than the other species tested) and dominated the HRAP at > 90% of the algae population during continuous mode. Addition of HMTBA (> 1 mg.L-1) to algae cultivation systems and those treating wastewater, has the potential to improve productivity and the value of the biomass by enhancing protein content. Overall, the co-utilisation of microalgae for wastewater treatment and the generation of a biomass rich in protein, for incorporation into formulated animal feed supplements, represents a closed ecosystem which conserves nutrients and regenerates a most valuable resource, water.]]> Wed 12 May 2021 15:55:36 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4048 Wed 12 May 2021 15:55:08 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3935 Wed 12 May 2021 15:49:47 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:41036 Wed 12 May 2021 14:38:58 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4032 Wed 05 Apr 2023 07:00:15 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4136 Thu 13 May 2021 10:28:15 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3939 Thu 13 May 2021 08:52:34 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3884 Thu 13 May 2021 08:52:00 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:31489 Thu 13 May 2021 08:49:59 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4023 Thu 13 May 2021 08:13:31 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4010 Thu 13 May 2021 07:34:45 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4104 Thu 13 May 2021 07:27:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3929 Thu 13 May 2021 07:14:41 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3919 Thu 13 May 2021 07:05:18 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3959 Thu 13 May 2021 07:01:49 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4133 Thu 13 May 2021 06:54:33 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4046 Thu 13 May 2021 06:51:04 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4073 Thu 13 May 2021 06:37:23 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3968 Thu 13 May 2021 06:31:22 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4062 Thu 13 May 2021 06:26:33 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4020 Thu 13 May 2021 06:21:51 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4052 Thu 13 May 2021 06:17:48 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3938 Thu 13 May 2021 06:15:11 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3944 Thu 13 May 2021 06:01:30 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3958 Thu 13 May 2021 05:51:33 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3897 Thu 13 May 2021 05:43:16 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:31228 Thu 13 May 2021 05:39:44 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3922 Thu 13 May 2021 05:34:41 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3904 Thu 13 May 2021 05:05:44 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3917 Thu 13 May 2021 05:04:53 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3928 Thu 13 May 2021 05:03:04 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4124 Thu 13 May 2021 05:02:48 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3952 Thu 13 May 2021 04:58:57 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4128 Thu 13 May 2021 04:58:25 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3969 Thu 13 May 2021 04:40:19 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3911 Thu 13 May 2021 04:33:30 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4041 Thu 13 May 2021 04:32:37 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4029 Thu 13 May 2021 04:31:38 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4083 Thu 13 May 2021 04:19:34 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4012 Thu 13 May 2021 03:57:39 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3880 Thu 13 May 2021 03:40:51 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3916 Thu 13 May 2021 03:16:52 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4170 Thu 13 May 2021 03:15:16 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4015 chitin> glucan > intact cell walls exists. However, these components differ in their affinities for metal ions. Storage of metal ions within the cell occurs predominantly in the vacuole. The present study concluded that metal accumulation by the vacuole could be related to size. Metal accumulation occurred in the order of Cu2+ > Co2+ > Cd2+ with a corresponding decrease in atomic radii of Cd2+ > C02+ > Cu2+. Vacuolar ion deposition occurs at an early stage during the internalization of metal ions within the yeast cells. At the onset of vacuolar saturation, depositions of metal ions as granules within the cytosol occurs. In the presence of heavy metal cations viable yeast cells can be shown to exhibit two types of cellular responses. Uptake of Cu2+ and Cd2+ causes the loss of intracellular physiological cations from within the yeast cell. In comparison, uptake of Co2+ into the cell does not have this effect. All three heavy metal cations initiate plasma cell membrane permeability, thus the Cu2+ and Cd2+ induced loss of the intracellular cations, occurs. ~ a result of ion-exchange mechanisms and not due to cation leakage brought about by membrane permeabilization. Uptake of heavy metals by viable yeasts appears to be generally non-selective though the amount of metals accumulated are largely affected by the ratio of ambient metal concentration to biomass quantity. In addition, the energy dependent nature of internalization necessitates the availability of an external energy source for metal uptake by viable yeast cells. For these reasons metal removal from industrial waste water was investigated using non-viable biomass. By immobilizing the yeast cells additional mechanical integrity and stability was conferred apon the biomass. The three types of biomass preparations developed in this study, viz. polyvinyl alcohol (PV A) Na-alginate, PV A Na-orthophosphate and alkali treated polyethylenimine (PEI):glutaraldehyde (GA) biomass pellets, all fulfilled the necessary physical requirements. However, the superior metal accumulating properties of the PEI:GA biomass determined its selection as a biosorbent for bioremediation purposes. Biosorption of heavy metals by PEI:GA biomass is of a competitive nature, with the amount of metal accumulated influenced by the availability of the metal ions. This availability is largely determined by the solution pH. At low pH values the affinity of the biomass for metals decreases, whilst enhanced metal biosorption occurs at higher pHs, ego pH 4.5 - 6.0. PEI:GA biomass pellets can be implemented -as a biosorbent for the bi9remediaiton of high concentration, low-volume metal containing industrial waste. Several options regarding the bioremediation system are available. Depending on the concentration of the metals in the effluent, the bioremediation process can either be used independently or as part of a biphasic remediation system for the treatment of waste water. Initial phase chemical modification may be required, whilst two types of biological systems can be implemented as 'part of the second phase. The PEI:GA biomass can either be contained within continuous-flow fixed bed tanks or continuous-flow stirred bioreactor tanks. Due to the simplicity of the process and the ease with which scale-up is facilitated, the second type of system shows greater application potential for the treatment of this type of industrial waste water than the fixed-bed systems.]]> Thu 13 May 2021 02:58:09 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3918 Thu 13 May 2021 02:17:58 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4117 Thu 13 May 2021 02:12:44 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3967 Thu 13 May 2021 02:10:17 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4045 Thu 13 May 2021 02:07:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3890 Thu 13 May 2021 01:56:09 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4109 Thu 13 May 2021 01:52:04 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3930 Thu 13 May 2021 01:44:19 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3937 Thu 13 May 2021 01:19:45 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3900 Thu 13 May 2021 01:07:11 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4031 Thu 13 May 2021 01:00:06 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:26590 Thu 13 May 2021 00:39:44 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4025 Thu 13 May 2021 00:34:02 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4018 Thu 13 May 2021 00:24:29 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4114 Thu 13 May 2021 00:22:21 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4004 Thu 13 May 2021 00:20:34 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:3936 Thu 13 May 2021 00:16:00 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:45334 Fri 19 Nov 2021 09:15:59 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:45333 Fri 19 Nov 2021 08:33:53 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4028 Fri 06 Aug 2021 10:23:20 SAST ]]>