Research Publications (Applied Sciences)
Permanent URI for this collectionhttp://ir-dev.dut.ac.za/handle/10321/213
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Item Purification and characterization of an Endoinulinase from Xanthomonas campestris pv. phaseoli KM 24 Mutant(University of Zagreb, 2015) Naidoo, Kameshnee; Kumar, Ajit; Sharma, Vikas; Permaul, Kugen; Singh, SurenAn extracellular endoinulinase from Xanthomonas campestris pv. phaseoli KM 24 mutant was purifi ed to homogeneity by gel fi ltration chromatography and showed a specifi c activ-ity of 119 U/mg. The optimum pH and temperature of the purifi ed enzyme were found to be 6.0 and 50 °C, respectively. The enzyme was stable up to 60 °C, retaining 60 % of residu-al activity for 30 min, but inactivated rapidly above 60 °C. The enzyme was found to be stable at pH=6–9 when it retained 100 % of its residual activity. The Lineweaver-Burk plot showed that the apparent Km and vmax values of the inulinase when using inulin as a sub-strate were 1.15 mg/mL and 0.15 μM/min, respectively, whereas the kcat value was found to be 0.145 min–1. The calculated catalytic effi ciency of the enzyme was found to be 0.126 (mg·min)/mL. The purifi ed inulinase can be used in the production of high fructose syr-ups.Item Biodegradation of glycerol using bacterial isolates from soil under aerobic conditions(Taylor and Francis, 2014) Raghunandan, Kerisha; Mchunu, Siphesihle; Kumar, Ashwani; Kumar, Kuttanpillai Santhosh; Govender, Algasan; Permaul, Kugen; Singh, SurenGlycerol, a non-biodegradable by-product during biodiesel production is a major concern to the emerging biodiesel industry. Many microbes in natural environments have the ability to utilize glycerol as a sole carbon and energy source. The focus of this study was to screen for microorganisms from soil, capable of glycerol utilization and its conversion to value added products such as ethanol and 1,3-propanediol (1,3-PDO). Twelve bacterial isolates were screened for glycerol utilization ability in shake flask fermentations using M9 media supplemented with analytical grade glycerol (30 g/L) at various pH values (6, 7 and 8) and temperatures (30◦C, 35◦Cand 40◦C). Among these, six bacterial isolates (SM1, SM3, SM4, SM5, SM7 and SM8) with high glycerol degradation efficiency (>80%) were selected for further analysis. Highest level of 1,3-PDO production (15 g/L) was observed with isolate SM7 at pH 7 and 30◦C, while superior ethanol production (14 g/L) was achieved by isolate SM9 at pH 8 and 35◦C, at a glycerol concentration of 30 g/L. The selected strains were further evaluated for their bioconversion efficiency at elevated glycerol concentrations (50–110 g/L). Maximum 1,3-PDO production (46 g/L and 35 g/L) was achieved at a glycerol concentration of 70 g/L by isolates SM4 and SM7 respectively, with high glycerol degradation efficiency (>90). Three isolates (SM4, SM5 and SM7) also showed greater glycerol tolerance (up to 110 g/L). The isolates SM4 and SM7 were identified as Klebsiella pneumoniae and SM5 as Enterobacter aerogenes by 16S rDNA analysis. These novel isolates with greater glycerol tolerance could be used for the biodegradation of glycerol waste generated from the biodiesel industry into value-added commercial products.Item Improvement of ethanol production from sugarcane molasses through enhanced nutrient supplementation using Saccharomyces cerevisiae(Academic Journals, 2012-03) Nofemele, Zuko; Shukla, Pratyoosh; Trussler, Arthur; Permaul, Kugen; Singh, SurenSaccharomyces cerevisiae as a yeast cream was utilized for alcoholic fermentation using sugar cane molasses. In the present study, fermentation was optimized for urea and yeast hydrolysate (YH) dosage and the combined effect was evaluated. Total sugars as inverts (TSAI) composition of molasses were -1 determined by HPLC as 39% (m/v). Urea concentrations of 4, 2 and 3 gl showed optimal ethanol -1 production at 30, 35 and 40°C respectively. A YH concentration of 0.5 gl resulted in an ethanol yield of 8.7% (m/v) with a fermentation efficiency of 85.12%. Under optimized conditions (35°C) significant improvements were noticed with ethanol yield of 7.8% (m/v) and efficiency of 76.3%.Item Xylanase superproducer : genome sequence of a compost-loving thermophilic fungus, thermomyces lanuginosus strain SSBP(American Society for Microbiology, 2013-06-20) Mchunu, Nokuthula Peace; Permaul, Kugen; Rahman, Ahmad Yamin; Saito, Jennifer A.; Singh, Suren; Alam, MaqsudulWe report here the draft genome sequence of Thermomyces lanuginosus strain SSBP, which was isolated from soil in South Africa. This fungus produces the largest amount of xylanase ever reported in the literature.