Browsing by Author "Geeta G. Shirnalli"
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ThesisItem Open Access Isolation and Characterization of Cellulolytic Yeasts for Bioethanol Production(UAS, Dharwad, 2013) Sarat Chandra Sahoo; Geeta G. ShirnalliThe present study was conducted in the Department of Agricultural Microbiology on bioethanol production from selected agro-residues with the objectives whether two step process i.e. hydrolysis and fermentation could be transformed into single step with the help of efficient cellulolytic yeast strains, thus reducing the cost of bioethanol production. A total of 104 yeast isolates from various natural habitat mainly rotten fruit rinds, forest leaf litter, compost, fruit samples, food stuff and over matured paragrass were isolated on the basis of zone of hydrolysis of cellulose and release of reducing sugars. Among these 31 cellulolytic yeasts were screened. Five efficient strains CY-52, CY-58, CY-59, CY-62 and CY-81 were chosen on the basis of release of maximum reducing sugars. The isolates were subjected for utilization of various carbon sources namely glucose, maltose, ribose, lactose, sucrose, arabinose, galactose, xylose and starch to know the sugar utilization efficiency. The efficient yeast strains were subjected on two delignified substrates i.e. paddy straw and sugarcane bagasse. Delignification was carried out using alkali at 3 per cent for 8 h. Recovery of cellulose was highest in case of sugarcane bagasse i.e. 695 mg g-1 as compared to paddy straw 564 mg g-1.To know the enzymatic assay, filter paper activity and CMCase activity was conducted with the efficient strains out of which strain CY-59 isolate showed the highest activity i.e. 16.82 U ml-1 and 12.99 U ml-1 respectively. The yeast isolate CY-59 showed the maximum bioethanol production of 48.18 mg g-1 and 60.51 mg g-1 from paddy straw and sugarcane bagasse respectively which was on par to reference strain NCIM-3200and commercial cellulase. Thus, it can be concluded that yeasts are able to induce cellulase for hydrolysis of the substrates and produce ethanol. Extrapolating more sources from nature can yield better strains.ThesisItem Open Access Isolation and Charcterization of butanol Producing Clostridiumisolates from Diverse Sources(UAS, Dharwad, 2013) Rajashkar M. Uppin; Geeta G. ShirnalliThere is an incessant fluctuation in oil prices besides increasing stress from environmental pollution. The microbial production of biofuel from renewable sources is gaining interest. Biobutanol has advantages over traditional fuel ethanol in terms of energy density and hygroscopicity. Therefore, the present study was conducted to isolate and characterize butanol producing Clostridium sp from diverse sources. In the present study, 42 samples including soil, spoilt fruits etc. were collected from various natural sources from different locations of zone 8 of North Karnataka. A total of 130 biobutanol producing Clostridium isolates were isolated following standard Hungates roll tube technique. All the isolates that were Gram positive and forming endospores were considered to be Clostridium sp. Among these 47 isolates showed positive for indole production and gelatin liquefaction which are the main characters of Butanol producing Clostridium sp. Based on the rifampicin sensitivity, curd formation and riboflavin production the isolates were tentatively identified as, C. acetobutylicum, C.NCP 262, C. saccharoper butylacetonicum and C. beijerinckii. Fifteen isolates were selected based on their sources for detection of organic acids viz., acetic, propionic and butyric acid by high performance liquid chromatography. The highest production of acetic acid 37.11 mg ml-1 was detected in CL-26(3) and the highest butyric acid of 3.49 mg ml-1 was detected in CL-12(2) and the highest production of propionic acid was found in CL-40(4) was 30.69 mg ml-1, The strain ATCC 824 produced 30.80 mg ml-1 of acetic acid, 6.85 mg ml-1 of butyric acid and 0.61 mg ml-1 of propionic acid respectively. The wide variations in the production of organic acids indicated genetic variability. Majority of the isolates belong to C. acetobutylicum, which was habituated in diverse sources. Thus, efficient strains can be screened for butanol production from biomass.ThesisItem Open Access Mass Production of Microalgae for Bio-Diesel Production(UAS, Dharwad, 2012) Dhananjaya K.P.; Geeta G. ShirnalliMicroalgae are currently considered to be one of the most promising alternative sources for biodiesel production. In order to identify the potential microalgae for bio-diesel production, the present study was conducted. Twelve pure microalgal cultures were isolated from various water samples and were identified up to genera level. Four reference strains Botryococcus braunii (Ref strain1), Neochloris oleoabundans, (Ref strain 2) Botryococcus spp. (B6) and Scenedesmus dimorphus (SD7) were used in this study. Further, biomass production and lipid content were analysed. The highest biomass production was noticed in the reference strain Botryococcus braunii 3.45 g l-1 followed by Chlorella spp. (C3) which produced 3.2 g l-1. The lipid production in these isolates were 1.73 g l-1 and 1.60 g l-1 respectively. Four reference strains along with a local isolate Chlorella spp. (C3) were grown in 3 L bottle amended with four treatments{Sodium nitrate (8.5 mM L-1), Sodium carbonate (0.2 g l-1), Ferric ammonium citrate (42.8 μM) and a control}. Among them Ferric ammonium citrate showed maximum biomass, chlorophyll content and lipid yield i.e. in Botryococcus braunii 3.58g l-1, 10.64μg ml-1, and 1.87 g l-1 respectively, followed by Chlorella spp. (C3) which recorded 2.82 g l-1, 8.26 μg ml- 1 and 1.42 g l-1 respectively. The promising two microalgae viz. Botryococcus braunii and Chlorella spp. (C3) were grown in open tanks. Observations were recorded at 14, 18 and 21 DAI (Days after Inoculation). The biomass, chlorophyll and lipid yield of 3.50 g l-1, 10.55 μg ml-1 and 1.74 g l-1 respectively were recorded in Botryococcus braunii followed by Chlorella spp. (C3) which recorded 2.69 g l-1, 8.74 μg ml-1 and 1.29 g l-1respectively. The lipid extract from Chlorella spp. (C3) was subjected for trans-esterification process using alkali. Approximately, 70 ml bio-diesel was obtained from 100ml of lipid.ThesisItem Open Access Studies on beer production from different minor millets(UASD) Kamalakar R. Bolegaon; Geeta G. ShirnalliThe minor millet grains were screened for their suitability for beer production based on the amylase activity and reducing sugars of malted grains. Standardization of the parameters for malting and mashing were also carried out along with optimization of fermentation parameters for good quality beer production. The millet grains “Finger millet” showed the highest amylase activity (23.50 mg protein/15 min/g sample) and reducing sugars (25.30 mg/g) for a soaking period of 16h and germination period of two days which was followed by ‘Little millet’, ‘Foxtail millet’ and Bajra’. The ‘Finger millet’ was further used to standardize other parameters. The commercial a-amylase (MAPS India Ltd., Ahmedabad) was used during mashing process, at a concentration of 1 per cent at 70 °C for an incubation period of 24 h which released maximum reducing sugars (74.19 mg/g) than other treatments. Five strains of Yeast was screened for fermentation of the above hydrolysis and the optimization of the inoculum level and fermentation period were carried out. Among the inoculum levels used (1, 1.5 and 2%), the tannin content and residual reducing sugars of beer decreased significantly up to 2 per cent inoculum. The alcohol content increased as inoculum level increased. Among the yeast strains, Saccharomyces cerevisiae NCIM 3551 performed best when inoculated at 2 per cent inoculums level. The final beer produced was compared with the commercial beer and was favourable when evaluated organoleptically.ThesisItem Open Access Studies on Bioethanol Production From Selected Agro-Residues(UAS Dharwad, 2011) T.H. Shankarappa; Geeta G. ShirnalliThe present study was conducted on bioethanol production from selected agroresidues with the objectives of achieving higher recovery of fermentable sugars through delignification and saccharification followed by fermentation of the derived sugars to bioethanol. Five agro-residues namely sugarcane bagasse, sugarcane tops, sugarcane trash, corn husk and corn stover of particle sizes 0.5, 1.0 and 10.0 mm were delignified by various pre-treatment methods such as alkali, autohydrolysis and lignolytic fungi. The treatment combination of 3.0% NaOH with 1210C temperature for one h on particle size 0.5 mm resulted in the highest recovery of cellulose and hemicelluloses in sugarcane bagasse (0.813 g/g), sugarcane tops (0.786 g/g), sugarcane trash (0.806 g/g), corn husk (0.806 g/g) and corn stover (0.806 g/g). The delignified substrates were further saccharified using cellulolytic fungi and their crude enzymes and commercial cellulase enzymes. Among these, the commercial cellulase enzyme with 15 U/g along with b-glucosidase (10 U/g ) and Xylanase (5 U/g) enzymes at 5% substrate produced significantly highest reducing sugars with per cent saccharification in sugarcane bagasse (93.17%), sugarcane tops (90.33%), sugarcane trash (84.61%), corn husk (80.61%) and in corn stover (80.80%) in 12 h of incubation period. The pre-treated substrates were fermented to bioethanol by using six microorganisms. The combined inoculation of Saccharomyces cerevisiae and Candida shihatae on pre-treated substrates resulted in the highest ethanol yield in all the substrates, sugarcane bagasse (278.40 mg/g) followed by sugarcane tops (262.75 mg/g), sugarcane trash (241.42 mg/g), corn stover (239.82 mg/g) and corn husk (232.36 mg/g). The scaled up study on bioethanol production with sugarcane bagasse under optimized conditions produced 223 g bioethanol from one kg pre-treated substrate. Thus, it can be concluded that the substrates need to be alkali pretreated followed by treatment with commercial enzymes and further conversion to ethanol. The combined inoculation of the yeast cultures yields maximum ethanol.