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20134
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Subject: Agricultural Meteorology ×

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    ThesisItemOpen Access
    Bioprospecting of pectinase enzymes from fungi
    (UASD) Dushyantha D. K.; K. S. Jagadeesh
    The present study was conducted to isolate, and characterize fungi from diverse natural sources capable of producing pectinases. Based on the preliminary screening of 100 isolates, 48 isolates were found positive for pectinase production. Out of them, isolates RBF96 (3.25), RC27 (3.21) and DLP51 (3.21) possessed the highest potency index values compared to the reference strain Aspergillus niger MTCC1344 (2.99). Following the PCR based molecular methods, the isolates were identified as Aspergillus niger, Aspergillus oryzae and Penicillium citrinum respectively. Solid state fermentation (SSF) was carried out using various locally available agro-wastes as the carbon source. Citrus peel was identified as the most suitable substrate. The particle size of 2 mm, moisture level of 65 per cent, incubation temperature of 35oC, inoculum level of 1 x 107 spores g-1 and the incubation time of six days were found optimum. After purification the maximum specific activity of 83.06 U μg-1 protein was obtained for polygalacturonase (PG) by A. niger RBF96 with seven fold increase in purification. Similarly, about six folds and five folds increases in purification were obtained for pectin lyase (PL) and pectin esterase (PE) in P. citrinum DLP51 and A. oryzae RC27 respectively. The molecular weights of PG, PL and PE, as determined by SDSPAGE, were 45 kDa, 37 kDa and 31 kDa respectively. The purified PG showed maximum stability at pH 4.5, whereas, PL and PE showed at pH 6.5 and 5.0 respectively. The temperature of 50oC was found optimum. The orange pulp treated with (PG+PL+PE) at 100 U resulted in the highest juice yield (90.17%) and the highest clarity (96.28%). Similarly, in guava this treatment resulted in the highest juice yield (66.75%) and maximum clarity (37.57%). The organoleptic evaluation proved that pectinases could be used to improve the sensorial attributes of fruit juices.
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    ThesisItemOpen Access
    Isolation and Characterization of Cellulolytic Yeasts for Bioethanol Production
    (UAS, Dharwad, 2013) Sarat Chandra Sahoo; Geeta G. Shirnalli
    The 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.
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    ThesisItemOpen Access
    Studies on Bacteria Solubilizing both Potassium and Phoshorus and Their Effect on Maiza (Zea Mays L.)
    (UAS, Dharwad, 2013) Basavesha K.N.; V.P. Savalgi
    Bacteria solubilizing both potassium and phosphorus isolated by soil samples collected from different rhizosphere and crops from Dharwad, Haveri and Davanagere districts of Karnataka. The total 50 bacterial isolates were tested for their potassium and phosphrous solubilization and characterized upto genus level based on morphological and biochemical characters. In vitro evaluation of potassium and phosphorus solubilization by bacteria tested at different days after incubation (DAI). The maximum solubalization of K and P observed at 15 DAI ranges from 2.36 to 29.83 μg/ml and 3.44 to 14.25 per cent respectively. All the isolates were tested for beneficial traits like production of growth promotion substance and the amount of IAA and GA produced by the isolates ranged from 3.38 to 8.90 μg/25ml and 1.27 to 3.67 μg/25ml respectively. The efficient eight isolates of Bacillus species which solubilize both potassium and phosphorus was examined for their influence on growth, yield and nutrient content of maize plant under green house condition. All the inoculated treatment with bacteria were recorded maximum dry matter content at 30, 60, and at harvest recorded in isoaltes K-PSB 32 with rock phosphate and mica were 12.80, 44.2 and 235.7 g/plant, respectively. The yield components as compared with uninoculated fertilizer control, the isolate K-PSB 50 with rock phosphate and mica were recorded the heights cob weight 144.9 g/plant and the highest grain yield 52.93 g/plant and other parameters, followed by isolate K-PSB 32 with rock phosphate and mica. From the present study, it was concluded the bacterial isolates K-PSB 50 and K-PSB 32 were efficient K-PSB isolates. They capable to solubilize both K and P from the mineral source of mica and tricalcium phosphate respectively under in vitro condition. They produced plant growth promoting substances such as IAA and GA resulting in increased biomass, total dry matter and cob yield of maize plant.
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    ThesisItemOpen Access
    Studies on Zinc Solubilizing Bacteria and Their Effect on Growth and Yield of Maize (Zea Mays L.)
    (UAS, Dharwad, 2013) Shruthi P.; V.P. Savalgi
    Attempts were made to isolate zinc solubilizing bacteria from rhizosphere soil of different crops from Dharwad and Belgaum districts. A total of 30 bacteria isolates were tested for Zn solubilization and characterized upto genus level based on morphological and biochemical characters. The mechanisms involved in Zn soluiblization and other agronomical beneficial traits were also analyzed for selected efficient strains. In vitro Zn solubilization by bacteria ranged from 5.57 ppm to 13.57 ppm. Gluconic acid was the main organic acid produced by the ZSB isolates. Thirteen isolates were tested for other beneficial traits like production of organic acid, production of siderophore and production of growth promoting substance. All the thirteen isolates produced gluconic acid. The amount of siderophore produced by the strains ranged from 0.35 to 0.91 μg/ml. The amount of IAA and GA produced by the strains ranged from 5.43 to 10.67 and 1.07 to 2.77 μg/ 25 ml respectively. Two efficient gram negative Zn soluiblizing bacteria were also examined for their influence on growth and yield of maize plants under glass house condition. All the treatment with combined inoculation of ZSB-1 and ZSB-2 were found to increase growth parameters, nutrient content and yield components compared to control and with single inoculation of ZSB. The treatment T16 (ZSB-1 + ZSB-2 + RD of NPK + 100% Zn) recorded the highest yield (75.70 g/plant) and other parameters followed by T15 and T14 (73.5 and 71.7 g/plant respectively). Population of ZSB, PSB, N2 fixers and dehydrogenase activity in rhizosphere soil of maize were significantly higher in the treatment inoculated with ZSB-1 + ZSB-2 as compared to control and single inoculation. Thus it can be inferred that combined inoculation of zinc solubilizing bacteria have the potential to be use as bioinoculants
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    ThesisItemOpen Access
    Isolation and Charcterization of butanol Producing Clostridiumisolates from Diverse Sources
    (UAS, Dharwad, 2013) Rajashkar M. Uppin; Geeta G. Shirnalli
    There 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.