https://nova.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:51986 Wed 28 Feb 2024 14:50:44 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:53252 Wed 28 Feb 2024 14:46:56 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:43200 Wed 22 Mar 2023 10:38:47 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:44477 Desmodesmus sp. MAS1 and Heterochlorella sp. MAS3, were assessed for their ability in iron (Fe) removal from an AMD sample in nonimmobilized and immobilized systems. Use of free and immobilized cells exhibited 46−48% and 65−79% Fe removal, respectively, after 48 h of incubation. Compared with free cells, immobilized cells exhibited no apparent changes in morphology and granularity, as revealed by flow cytometry analysis, after their exposure to AMD samples. The second derivative spectra from Fourier transform infrared spectroscopy showed vibrational stretching for proteins and hydroxyl groups in immobilized cells. Thus, the immobilization technology offers a protective mechanism in acid-adapted strains against Fe present in AMD samples. Analysis of the immobilized acid-adapted microalgal technology by life cycle assessment (LCA) revealed its environmental sustainability because of less contribution to global warming and limited fossil fuel consumption. We demonstrated that the immobilized acid-adapted microalgal technology is much superior to calcined eggshell−microalgal or conventional limestone systems indicated in the literature for AMD treatment. Thus, this is the first study describing the potential application of microalgal cells entrapped in alginate beads in a greener and economical approach to treat AMD for sustainable mining.]]> Wed 07 Feb 2024 16:37:48 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:48292 90%) to the overall emergy and were much lower than in passive and active treatment systems. The microalgal treatment required 2–15 times more renewable inputs than the other two treatment systems. Additionally, the emergy indices indicated higher environmental loading ratio and lower per cent renewability, suggesting the need for adequate renewable inputs in the immobilized microalgal system. The emergy yield ratio for biodiesel production from the microalgal biomass after AMD treatment was >1.0, which indicates a better emergy return on total emergy spent. Based on greenhouse gas emissions, carbon footprint analysis (CFA), was performed using default emission factors, in accordance with the IPCC standards and the National Greenhouse Energy Reporting (NGER) program of Australia. Interestingly, CFA of acid-adapted microalgal technology revealed significant greenhouse gas emissions due to usage of various construction materials as per IPCC, while SCOPE 2 emissions from purchased electricity were evident as per NGER. Our findings indicate that the immobilized microalgal technology is highly sustainable in AMD treatment, and its potential could be realized further by including solar energy into the overall treatment system.]]> Wed 07 Feb 2024 14:55:19 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:52592 Wed 07 Feb 2024 14:32:04 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:52893 Wed 07 Feb 2024 14:23:53 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:54426 Tue 27 Feb 2024 13:59:05 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:54438 Tue 27 Feb 2024 13:56:17 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:50961 Tue 22 Aug 2023 11:24:20 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:37098 Tue 18 Aug 2020 09:48:42 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:51611 92%), PO43−-P (>89%) and COD (>84%) as well as increased production of ROS and neutral lipids, indicating their significant mutualistic interactions with the native bacterial communities for efficient bioremediation of wastewaters. Analysis of 16S rRNA gene-based community data in wastewaters revealed selective enrichment of Firmicutes and Actinobacteria, resulting in enhanced microalgal growth and nutrient removal. The findings of this novel study suggest that microalgal–bacterial co-cultures mediate interspecies interactions for a shift in population dynamics of the indigenous bacteria in wastewaters to facilitate enhanced bioremediation of effluents with sustainable production of biomass and biodiesel.]]> Tue 12 Sep 2023 13:42:26 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:44296 1.5-fold). Strain MAS1 grown at pH 3.5 showed a reduction (1.5-fold) in carbohydrates while strain MAS3 exhibited a 17-fold increase in carbohydrates as compared to their growth at pH 6.7. However, lower levels of biologically excess concentrations of the selected transition metals at pH 6.7 unveiled positive or no effect on physiology and biochemistry in microalgal strains, whereas growth with higher metal concentrations at this pH resulted in decreased chlorophyll content. Although the bioavailability of free-metal ions is higher at pH 3.5, as revealed by Visual MINTEQ model, no adverse effect was observed on chlorophyll content in cells grown at pH 3.5 than at pH 6.7. Furthermore, increasing concentrations of Fe, Mn and Zn significantly upregulated the carbohydrate metabolism, but not protein and lipid synthesis, in both strains at pH 3.5 as compared to their growth at pH 6.7. Overall, the impact of pH 3.5 on growth response suggested that acclimation of microalgal strains to acidic pH alleviates metal toxicity by triggering physiological and biochemical changes in microalgae for their survival.]]> Tue 11 Oct 2022 16:05:47 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:39314 Variovorax paradoxus IS1, all isolated from wastewaters. Tetradesmus obliquus IS2 and Coelastrella sp. IS3 were further selected for gaining insights into physiological changes, including those of metabolomes in consortia involving V. paradoxus IS1. The distinct parameters investigated were pigments (chlorophyll a, b, and carotenoids), reactive oxygen species (ROS), lipids and metabolites that are implicated in major metabolic pathways. There was a significant increase (>1.2-fold) in pigments, viz., chlorophyll a, b and carotenoids, decrease in ROS and an enhanced lipid yield (>2-fold) in consortia than in individual cultures. In addition, the differential regulation of cellular metabolites such as sugars, amino acids, organic acids and phytohormones was distinct among the two microalgal-bacterial consortia. Our results thus indicate that the selected microalgal strains, T. obliquus IS2 and Coelastrella sp. IS3, developed efficient consortia with V. paradoxus IS1 by effecting the required physiological changes, including metabolomics. Such microalgal-bacterial consortia could largely be used in wastewater treatment and for production of value-added metabolites.]]> Tue 09 Aug 2022 14:26:20 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:37155 Thu 21 Oct 2021 12:44:49 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:48429 Thu 16 Mar 2023 14:18:03 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:50088  twofold) than ammonium, while the bacterial strain cultured with ammonium alone exhibited a > 1.3-fold increase in growth than nitrate. Co-culturing performed higher growth at combined nitrate and ammonium supply as compared to the single cultures. The same ratio of nitrate and ammonium resulted in superior growth of microalgae (> 1.7-fold) and the bacterium (> 4.1-fold) as compared to the monocultures. Uptake of NO3–N, NH4–N and PO4–P by monocultures or co-cultures depended on the ratio of two inorganic nitrogen sources used. The composition of organic acids, amino acids and simple sugars in exudates from monocultures varied with the ratios of nitrate and ammonium in the medium. Thus, the present novel study demonstrates that the release of exudates is affected both qualitatively and quantitatively during mutualistic interactions in microalgal‒bacterial co-cultures under the impact of inorganic nitrogen sources. Our results suggest that the variables such as inorganic nitrogen sources and extracellular metabolites released need to be considered while using co-cultures for effective bioremediation of wastewaters.]]> Thu 13 Jul 2023 10:13:24 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:45777 200%) in the release of exopolysaccharides that facilitated soil aggregate stability. The increase in soil pH was about one unit (from 4.8 to 5.6 in soil A or 4.3–5.3 in soil B) under the influence of individual or co-cultures of the microalgal strains after 90 days. Algalized acid soils exhibited a significant increase in carbon content (29–57%), dehydrogenase activity (>500%) and production of indole acetic acid (200–500%). Thus, the present study reports for the first time on the great potential of green microalgae in amelioration of acid soils besides improving soil health and fertility.]]> Sat 05 Nov 2022 12:27:56 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:44755 Mon 24 Oct 2022 08:42:50 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:37161 Mon 24 Aug 2020 16:04:57 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:37160 Mon 24 Aug 2020 15:57:43 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:37158 Desmodesmus sp. MAS1 and Heterochlorella sp. MAS3, isolated from neutral environments, for simultaneous removal of heavy metals such as copper (Cu), iron (Fe), manganese (Mn) and zinc (Zn), and production of biodiesel when grown at pH 3.5. Excepting Cu, the selected metals at concentrations of 10–20 mg L⁻¹ supported good growth of both the strains. Cellular analysis for metal removal revealed the predominance of intracellular mechanism in both the strains resulting in 40–80 and 40–60% removal of Fe and Mn, respectively. In-situ transesterification of biomass indicated enhanced biodiesel yield with increasing concentrations of metals suggesting that both these acid-tolerant microalgae may be the suitable candidates for simultaneous remediation, and sustainable biomass and biodiesel production in environments like metal-rich acid mine drainages.]]> Mon 24 Aug 2020 15:43:43 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:37157 Desmodesmus sp. MAS1 and Heterochlorella sp. MAS3, originally isolated from non-acidophilic environment, were tested for their ability to withstand higher concentrations of an invasive heavy metal, cadmium (Cd), at an acidic pH of 3.5 and produce biomass rich in biodiesel. The growth analysis, in terms of chlorophyll, revealed that strain MAS1 was tolerant even to 20 mg L^-1 of Cd while strain MAS3 could withstand only up to 5 mg L^-1. When grown in the presence of 2 mg L^-1, a concentration which is 400-fold higher than that usually occurs in the environment, the microalgal strains accumulated >58% of Cd from culture medium at pH 3.5. FTIR analysis of Cd-laden biomass indicated production of significant amounts of biodiesel rich in fatty acid esters. This is the first study that demonstrates the capability of acid-tolerant microalgae to grow well and remove Cd at acidic pH.]]> Mon 24 Aug 2020 15:36:43 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:37154 Desmodesmusv sp. MAS1 and Heterochlorella sp. MAS3, grown in synthetic acid mine drainage (SAMD). Virtually, there was no difference in the growth of the strain MAS3 both in Bold's basal medium (control) and SAMD. Using the IC₅₀ level (200 mg L^-1) and a lower concentration (50 mg L^-1) of iron in SAMD, the cell granularity, exopolysaccharide (EPS) secretion, iron recovery, and biodiesel were assessed in both the strains. Both cell granularity and accumulation of EPS were significantly altered under metal stress in SAMD, resulting in an increase in total accumulation of iron. Growth of the microalgal strains in SAMD yielded 12-20% biodiesel, with no traces of heavy metals, from the biomass. The entire amount of iron, accumulated intracellularly, was recovered in the residual biomass. Our results on the ability of the acid-adapted microalgal strains in iron recovery and yield of biodiesel when grown in SAMD indicate that they could be the potential candidates for use in bioremediation of extreme habitats like AMD.]]> Mon 24 Aug 2020 12:48:49 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:42319 Zn > Cr > Cu > Pb > Cd > Hg. Significant positive correlations exist between Cd and Zn, Cu and Pb, Cd and Hg, and Cr and Hg. Ecological risk indices denote predominant levels (> 70%) of cadmium throughout the sampling points as indicated from contamination factor. Potential ecological risk assessment specified the alarming levels of cadmium and mercury above the standard limits in the sediments assessed. Based on the observations, it is evident that the Cooum River is highly polluted and it becomes essential that the urban effluents should not be overlooked before their discharge into the river.]]> Mon 22 Aug 2022 10:39:17 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:46196 Mon 14 Nov 2022 11:15:57 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:37159 Desmodesmus sp. MAS1 and Heterochlorella sp. MAS3 can be acclimated to extreme-acidic pH for sustainable production of biomass and biodiesel. Growth analysis indicated that both the microalgal strains possessed a passive uptake of CO₂ at pH 3.0 with biomass production of 0.25 g dry wt. L⁻¹ in Desmodemus sp. and 0.45 g dry wt. L⁻¹ in Heterochlorella sp.. Flow-cytometry analysis for reactive oxygen species, membrane permeability and neutral-lipids revealed the capabilities of both strains to adapt to the stress imposed by acidic pH. Lipid production was doubled in both the strains when grown at pH 3.0. In-situ transesterification of biomass resulted in 13–15% FAME yield in the selected microalgae, indicating their great potential in biofuel production.]]> Mon 12 Apr 2021 15:05:01 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:51563 Mon 11 Sep 2023 11:12:51 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:51958 Fri 22 Sep 2023 17:04:44 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:54930 Fri 22 Mar 2024 14:32:28 AEDT ]]>