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Theses and dissertations (Applied Sciences)

Permanent URI for this collectionhttp://ir-dev.dut.ac.za/handle/10321/6

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    Production of oligosaccharides from lignocellulosic biomass
    (2020) Arumugam, Nanthakumar; Pillai, Santosh Kumar Kuttan; Singh, Suren
    Lignocellulosic biomass is the most abundant plant material present on earth which is primarily composed of cellulose, hemicellulose and lignin. The composition of lignocellulosic biomass varies depending on the type of plant material and the conditions at which the plant grow. Exploration of lignocellulose for the production of value-added compounds including all types of platform chemicals, biofuels and bioactive compounds is gaining momentum. However, extensive research needs to the carried out to minimize the cost of production to make the processing of this biomass more viable. In the last two decades, several agricultural biomass types have been studied to facilitate the production of biochemicals and biofuels at a low cost. Biomass such as peanut shells, bambara, cowpea and sorghum are some of the indigenous crops of South Africa that are yet to be explored for value addition. Therefore, this study was designed to characterize the underutilized agro-residues such as peanut shell, bambara, cowpea and sorghum biomass for the enzymatic production of prebiotic xylooligosaccharides (XOS) and their application.
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    Isolation and characterization of prebiotic oligosaccharides from algal extracts and their effect on gut microflora
    (2016) Hadebe, Nontando; Odhav, Bharti
    Prebiotics are defined as non-digestible oligosaccharides (NDOs) or polysaccharides (NDPs), which promote the growth of beneficial lactic acid bacteria in the colon. Algae are rich in polysaccharides and can be exploited as prebiotics for functional food ingredients to improve human and animal health. Currently, inulin is the most widely used ingredient in the prebiotics market, which is produced from live plants and requires expensive production processing. There is a vast repository of marine life with algae as a major source of nutrients. Therefore, this study provides an alternative source for prebiotic production and examines marine and freshwater algae that promote the growth of two strains of Lactobacillus delbrueckii subs. (Lactobacillus lactis and Lactobacillus bulgaricus) and one strain of Bifidobacterium spp. (Bifidobacterium longum). Monosaccharides of the oligosaccharide fraction of marine and freshwater algal extracts were investigated with the use of thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) after acidic hydrolysis of cell matrix polysaccharides. A total of fifty-five marine and freshwater aqueous algal extracts were assessed for their effect on the growth of L. lactis, B. longum and L. bulgaricus over a 96 hour period. Relative to the negative control, 34.5% algal extracts showed improved growth on one or more probiotic bacteria. The optimum time for maximum bacterial growth was noted at 48 h for all the tested aqueous algal extracts. Five marine and freshwater algal cultures (Spirulina platensis, Chlorococcum spp., Dunaliella salina, Scenedesmus magnus, Chlorella spp. and algal extract no. 48) from various aquatic environments in Kwa-Zulu Natal showed the best growth dynamics and demonstrated the greatest potential as sources of biomass for prebiotic production. These algal extracts were able to significantly increase the growth of at least one of the three probiotic bacteria (p < 0.05). Aqueous algal extract from S. platensis was regarded as the best algal source for prebiotics as it demonstrated a greater stimulatory effect on the growth of all three probiotic bacteria (L. lactis, B. longum and L. bulgaricus) compared to tested aqueous algal extracts and the inulin used as a positive control. The results obtained by HPLC for characterization confirmed TLC data, as xylose and galactose were detected by both chromatograms. These data indicated that xylose and galactose were present in aqueous algal extracts from S. magnus and S. platensis and galactose in aqueous algal extract no. 48. Xylose was most abundant in aqueous algal extracts from S. platensis (3mg/ml) and S. magnus (2.3mg/ml). In conclusion aqueous algal extracts from S. platensis, Chlorococcum, D. salina, S. magnus, Chlorella and algal extract no. 48 are potential sources for prebiotic production. Spirulina platensis extract was regarded as the best algal source. Xyose and galactose characterized by HPLC in algal extracts make up oligosaccharides that function as prebiotic compounds for stimulation of probiotic bacteria. There is a great scope for successful production of prebiotics from algal sources in South Africa.