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Browsing Journal Articles by browse.metadata.impactarea "Biomanufacturing Technologies"
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Item Biodegradation of petroleum hydrocarbon waste using consortia of Bacillus sp(2020-12) Masika, Wendy S; Moonsamy, Ghaneshree; Mandree, Prisha; Ramchuran, Santosh O; Lalloo, Rajesh; Kudanga, TPetroleum hydrocarbons are toxic to all forms of life; therefore, environmental pollution caused by petroleum is of great concern. Bio-based environmentally friendly strategies are preferred for the remediation of these contaminated sites. This study investigated the potential of consortia of Bacillus spp for the removal of petroleum hydrocarbons from synthetic media and industrial effluents. Of the 115 isolates, the top three performing isolates, designated as GPA 11.2, GPA 7.1, GPA 3.5, were selected and identified using 16 s rDNA as Bacillus subtilis (GPA 11.2), Bacillus methylotrophicus (GPA 3.5), and Bacillus amyloliquefaciens (GPA 7.1). The three strains were combined to produce three different consortia designated as prototype 1, prototype 2, and prototype 3. The bioremediation potential of each consortium was evaluated by Gas Chromatography (GC) using industrial effluents that contained hydrocarbons. Results indicated that the bulk of the contaminants were removed during the first 48 h; and removal (%) did not increase significantly after 72h. The total petroleum hydrocarbons (TPH) (C8–C28) removal rates from synthetic effluent after 48h of treatment using prototype 1, prototype 2, and prototype 3 were 64.9%, 30.0%, and 79.8%, respectively. The TPH (C8–C28) removal rate from true effluents after 48h of treatment using prototype 1, prototype 2, and prototype 3 consortia were 64.5%, 53.6%, and 52.7%, respectively. The results showed that the best performing consortium was prototype 1. This study has demonstrated the potential application of Bacillus consortia as bioremediation agents for the treatment of hydrocarbon-contaminated sites.Item Development of Bacillus spp. consortium for one-step “Aerobic Nitrification-Denitrification” in a fluidized-bed reactor(2022-02) Roets-Dlamini, Yrielle; Lalloo, Rajesh; Moonsamy, Ghaneshree; Kumari, S; Nasr, M; Ramchuran, Santosh O; Bux, FApplication of two-step “Autotrophic Nitrification and Anoxic Denitrification” for nutrients removal has found several limitations. This study aimed at isolating indigenous heterotrophic Bacillus strains for chemical oxygen demand (COD), ammonium nitrogen (NH4+-N), and phosphate (PO43--P) removal using one-step “Aerobic Nitrification-Denitrification”. Thirteen isolates were examined for growth performance, followed by bioremediation and enzymes production. B006, D005, and D014 were selected and shown to be safe for anthrax toxin and enterotoxin. B006 and D005 were identified as Bacillus cereus, whereas D014 had similarity to Bacillus subtilis. Three isolates were inoculated in a fluidized-bed reactor (FBR), achieving COD, NH4+-N, and PO43--P removal efficiencies of 74.42 ± 6.96, 62.66 ± 10.67, and 43.57 ± 10.23%, respectively within 11.3 h. The consortium attained adequate bioremediation capabilities when hydraulic retention time was decreased to only 5.7 h. This study showed environmental value in enhancing biological reactor performance using bio-augmentation, especially in small-scale and low-energy treatment systems.Item Performance evaluation of bio-based fractions derived from Bacillus spp. for potential in situ soil stabilisation(2022-02) Ramdas, Veshara; Lalloo, Rajesh; Mandree, Prisha; Mgangira, Martin B; Mukaratirwa, Samson; Ramchuran, Santosh OCurrent and future research focuses on the use of renewable technologies and materials to stabilise weak soils, of varying degrees, for road construction applications. Soil stabilisation is a method of strengthening a natural soil to meet this purpose. Our interest is in the use of bio-based components, derived from microbial growth processes, that contribute to the needed desirable strength characteristics for in situ soil stabilisation. This investigation focuses on novel Bacillus-based stabilisers obtained from the vegetative and spore growth stage. In this study, eighteen bio-based components were derived from a Bacillus licheniformisfermentation and extracted into various aqueous and non-aqueous fractions for strength property assessment. The strength properties of the treated soils (i.e., dolerite and weathered granite soil) were assessed via previously developed lab-scale equipment to rapidly pre-select the best performing fractions, (i.e., compression stress, erosion, abrasion, and water absorption tests). The effect of one superior performing prototype (a) was validated at large-scale, using standard erosion and abrasion tests (i.e., whole broth at 1.8% stabiliser concentrations), and showed resistance to abrasion (3.37 ± 0.03%) (p value = 0.0001) and resistance to erosion (33.20 ± 0.15%) (p value = 0.001). The elemental composition and microstructure of the bio-stabilised soil was determined using energy dispersive X-ray spectroscopy and scanning electron microscopy, respectively. This evaluation formed part of the selection of the best performing Bacillus derived fractions and achieved a proof of concept for the next phase of product prototype development. This study demonstrated a novel bio-mediated approach to the overall criteria for evaluation and selection of candidate product prototype/s, for stabilisation of two varying soils, and for potential application in road construction works.Item Production and stability of a multi-strain Bacillus based probiotic product for commercial use in poultry(2021-03) Ramlucken, Uraisha; Ramchuran, Santosh O; Moonsamy, Ghaneshree; Jansen van Rensburg, C; Thantsha, MS; Lalloo, RajeshProbiotics can be effective alternatives to the prophylactic use of antibiotic growth promoters (AGPs) in response to industry and consumer concerns around their use in poultry. Studies on the suitability of Bacillus probiotics are emerging and showing benefits, but information on the production technology is limited. We developed the production process for a novel probiotic product previously shown to be effective in field trials. All strains were cultivated to a spore concentration exceeding 1 × 1010 CFU. mL-1. The spores of each strain were harvested, processed into a powder intermediate and formulated into an end product with 100 % recoveries and a shelf life stability >1 year. The probiotic was shown to be incorporated into broiler feed exceeding the desired concentration of 1 × 106 CFU. g-1. Using efficient process technology and lower cost materials, this study presents a commercially relevant case for the potential adoption of probiotic products by the poultry industry.Item Review of current and future bio-based stabilisation products (enzymatic and polymeric) for road construction materials(2020-10) Malapermal Ramdas, Veshara; Mandree, Prisha; Mgangira, Martin B; Mukaratirwa, S; Lalloo, Rajesh; Ramchuran, Santosh OIn situ soil modification is required in order to improve the primary engineering properties of the material to meet a road construction standard. Bio-stabilised soil is an environmentally friendly, cost-effective alternative to imported granular fills, concrete, costly hauling of materials or export to a landfill. In-service soil performance and required maintenance is highly dependent on methods of stabilisation, ranging from expensive mechanical stabilisation to chemical processes. As such, many alternative materials originating from bio-based sources are being explored as potential stabilising additives to improve weak subgrade soils (i.e., dispersive, erodible and collapsible soil, and soft or expansive clays). Some key solutions include the use of bio-derived enzymes, microbes, and polymeric additives to avert road failure caused by water penetration and/or erosion. The role of microbial substrate specialisation has been largely unexplored, since the level of research done on alternative stabilisers consists mostly of small ad hoc studies. In addition, research has focused on a reduction in permeability and an increase in compressive strength using enzymes and polymers, however, the complexity of these products and their implementation for a wide range of soil types and structural applications remain limited. Currently there is a need for more supporting research methodologies and systematic approaches on the implementation of bio-based materials for infrastructure development. This also includes the simplification of bio-based products for potential construction applications. This review provides (a) an overview of soil stabilisation techniques, (b) the primary challenges that lay ahead for future research in bio-based stabilisation products application in the road sector and (c) innovations to address the challenges of using modernised techniques in the road construction industry (i.e., weak subgrade and the required maintenance thereof, as well as the development of potential bio-based additives for unpaved road construction application).Item Understanding the mechanism of interaction of candidate soil stabilizing prototypes by using microscopy and spectroscopy techniques(2021-05) Ramdas, Veshara M; Lalloo, Rajesh; Lekha, Prabashni S; Mgangira, Martin B; Muniyasamy, Sudhakar; Mukaratirwa, S; Ramchuran, Santosh OGlobally, there is a high demand for bio-based soil stabilizers required for improving the strength properties of weak in situ soil. Microbes and microbial components such as Bacillus spp. have gained interest as soil stabilizers due to their production of spores, bio-enzymes, and bio-polymers. However, the current approach for any microlevel assessment of bio-additives and in situ soil improvement is limited. This paper provides data for microstructural evaluation of stabilized soil material for the postulation of the mode of action. In this study, the microbonding effect (i.e., bio-based cementation, bio-clogging, and soil particle bio-coating) is successfully observed within the various stabilizing prototypes, obtained from a novel Bacillus spp. using advanced methods, namely field emission gun-scanning electron microscopy and Fourier transform-infrared spectroscopy. The results show that treated soil versus untreated soil properties are altered by the bio-additive/s stabilizing effect. These indicator tests provide data for further bio-stabilizer product prototype development and processes (i.e., improved products in terms of strength and moisture susceptibility). The use of microscopy and spectroscopy was sufficient for the preliminary selection of suitable candidates for soil stabilization.