Magister Scientiae - MSc (Biotechnology)
http://hdl.handle.net/11394/3105
2024-03-29T01:29:55ZBiochemical characterisation of an alpha-amylase with pullulan hydrolase type III characteristics derived from a hot spring metagenomics library
http://hdl.handle.net/11394/10688
Biochemical characterisation of an alpha-amylase with pullulan hydrolase type III characteristics derived from a hot spring metagenomics library
Boersma, Bianca
The field of metagenomics has provided biotechnological researchers with new enzymes and insight into previously unknown enzyme families with potential for novel modes of action and being able to function under extreme conditions, such as extremes of temperature, acidity or alkalinity. The enzymes can also often act on multiple substrates and show increased affinity for certain substrates. In this study, the aim was to biochemically characterise a putative type III pullulan hydrolase (PHTIII). A sequence-based metagenomic screen from previous performed by Xiao Ping Hu (2010) was used to identify novel glycosyl hydrolase enzymes in shotgun metagenomic sequence data from the Mphizi hot spring in Malawi. An identified ORF, named Pull3.1, displayed low sequence identity to a characterised α-amylase (62.71%) and 61.66% to a characterised pullulan hydrolase type III, and was, therefore, hypothesized to be an α-amylase (EC 3.2.1.1) with pullulan hydrolase type III (EC 3.2.1.x) characteristics. Further sequence analysis indicated that Pull3.1 had a glycogen binding site and that it belongs to the GH13_20 family as well as having a family 48 carbohydrate-binding module. Pull3.1 displayed the highest substrate conversion rates for starch, pullulan and glycogen. The products released were of the following degrees of polymerisation 3, 2 or 1, in accordance with the products released from the PHTIII from Thermococcus aggregans. Pull3.1 is a thermozyme that shows maximum activity at 75°C and an optimum pH of 7. It was thermostable up to 80°C and had a half-life of 11.6 min at 50°C. Further kinetic characterisation showed that Pull3.1 had a high affinity for starch. The KM value of 0.048 mg/ml is within the range reported for other α-amylase enzymes, and Pull3.1 had a Vmaxof 0,729 (μmol mL−1). All of this data indicates that Pull3.1 is a good candidate for a starch conversion process that requires thermozymes.
>Magister Scientiae - MSc
2024-01-01T00:00:00ZSouth African medicinal plant extracts used in the treatment of fungal infections.
http://hdl.handle.net/11394/10480
South African medicinal plant extracts used in the treatment of fungal infections.
Ndlovu, Banele Michelle
The incidence of fungal skin infections is increasing at an alarming rate, especially in people with underlying immunosuppressive conditions. Currently, the most used methods of treatment are in the azole group of synthetic treatments. A major problem with these synthetic treatments’ is the increase in azole-resistant strains spreading worldwide. Additionally, an estimated 65–80% of all fungal infections are biofilm related, with biofilms found in Candida species such as Candida albicans, Candida dubliniensis, Candida glabrata and Candida tropicalis which infect the skin.
There is an increased demand for alternative treatments that could be antifungals and medicinal plants could be the potential solution, as some plants possess antifungal properties. The overall aim of this study is to investigate the potential effect of South African medicinal plants used for the treatment of fungal infections against pathogens of dermatological relevance. The objectives were 1) to conduct a comprehensive literature search to identify indigenous medicinal plant extracts used to treat fungal skin infections, 2) to perform a cross-sectional study using an interview-based questionnaire to investigate the knowledge and practices of Cape bush doctors and validate their use of selected medicinal plants for treating dermatophyte infections in the Cape Metropole communities and 3) to investigate the in vitro bioactivity of selected plant extracts identified from the literature search and interviews.
Fifteen medicinal plants were found using an in-depth literature search and all 15 plants were validated during the interviews as plants commonly used for fungal skin infections.
>Magister Scientiae - MSc
2023-01-01T00:00:00ZValorisation of brewers’ spent grain: enzymatic hydrolysis in the production of xylooligosaccharides
http://hdl.handle.net/11394/10474
Valorisation of brewers’ spent grain: enzymatic hydrolysis in the production of xylooligosaccharides
Arries, Chelsey
The beverage industry constitutes approximately 26% of all food wastes, making it one of the largest contributors in this waste segment. By utilising waste or by-products from agriculture and food production in manufacturing value added compounds, the concepts of waste mitigation and green chemistry can contribute to establishing a circular bio-economy. In a biorefinery, bio-catalytic, thermal, chemical and physical techniques are used to extract valuable compounds from food and agricultural wastes. Brewers’ spent grain (BSG) is an ideal candidate for such a biorefinery approach. This high moisture, nutrient-rich by-product from beer production is either disposed of in landfills or used as an animal feed. However, high value products, such as xylooligosaccharides (XOS) can be extracted from BSG, thereby valorising this brewery waste. Xylooligosaccharides are sought after for their ability to function as a low caloric sweetener while exhibiting prebiotic effects in stimulating the growth of probiotic bacteria in the mammalian gut.
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2023-01-01T00:00:00ZAntibacterial effects of biogenic silver nanoparticles synthesized using manihot esculenta (cassava) leaf aqueous extract
http://hdl.handle.net/11394/10472
Antibacterial effects of biogenic silver nanoparticles synthesized using manihot esculenta (cassava) leaf aqueous extract
Oliver, Toni Charlize Alexia
Antimicrobial resistance (AMR) is a growing global health concern that poses a serious threat to the health of humans, animals, and plants. The major public health problem of AMR is primarily caused by the incorrect use of antibiotics, which is further compounded by the reduced novel antibiotics discovery rate. AMR bacteria cause infections that are difficult to treat, resulting in prolonged hospital stays and increased healthcare costs. Moreover, AMR is associated with a high risk of morbidity and mortality. Current therapeutic strategies for AMR infections are often inefficacious, associated with side effects, and may further exacerbate AMR. Therefore, there is an urgent need to develop alternative strategies to treat AMR bacterial infections.
>Magister Scientiae - MSc
2023-01-01T00:00:00Z