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2014 - 20194
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Subject: Microbiology × Author: Jaspreet Kaur × End date: 2019 × Start date: 2010 × Type: Thesis ×
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    ThesisItemOpen Access
    Development of bacterial consortium to improve green manure degradation and nutrient availability in kharif maize
    (Punjab Agricultural University, Ludhiana, 2019) Jaspreet Kaur; Gosal, S.K.
    The present investigation was conducted to isolate cellulose degrading bacteria with plant growth promoting traits to enhance green manure (Crotolaria juncea) decomposition as well as nutrient mineralization in maize crop. A total of 75 different bacteria were isolated from soil samples collected from various locations. Only 20 isolates were selected on their ability to degrade cellulose. Cultural and morphological characterization showed that most of these bacterial isolates were gram positive, non-motile and non-endospore forming cocci. Biochemical characterization of the isolates revealed that most of these isolates were positive for oxidase, catalase, methyl red, starch and citrate utilization test. Only two bacterial isolates (CD4 and CD6) were urease positive, one (CD11) was indole positive and three (CD1, CD11 and CD15) were found to HCN positive. Functional characterization of these isolates showed that the isolates CD2 and CD9 had highest cellulase (27.543 mg/ml) and β-glucosidase activity (15.46 μg pNP released/ml), respectively. Highest IAA production (42.25 μg/ml), phosphorous solubilization index (1.80) and quantitative P- solubilization (25.39 μg/ml) were recorded for CD9 bacterial isolate. All the isolates were found to have nitrogen fixing ability. The maximum amount of ammonia (6.659 μM/ml) was excreted by isolate CD18 on N-free Jensen‟s medium. On the basis of functional characteristics, three best isolates (CD2, CD9 and CD14) were evaluated for green manure decomposition and nutrient mineralization studies, under pot conditions under different soil (sterilized and unsterilized) and moisture regimes (aerobic and flooded). The application of isolates as consortium was found best for increasing green manure decomposition, nutrient mineralization and soil biological activities relative to uninoculated control treatments. These effects of consortium inoculation were found more pronounced in aerobic conditions as compared to flooded conditions. A field experiment was conducted for two consecutive years (2016 and 2017). A significant decomposition of green manure was observed with application of CDBC biofertilizer within the period of seven days in field condition. A total of eight treatments having different combinations of biofertilizer (CDBC), green manure and inorganic nitrogen fertilizers (75% and 100%) were used to study their effect on soil microbial dynamics, soil chemical properties and yield of maize crops (var. PMH1 and var. PMH4). Microbial population (total bacteria, fungi, P-solubilizer, amylolytic and cellulolytic bacteria) and enzymatic activities (dehydrogenase, alkaline phosphatase, urease, cellulase, amylase and invertase) in maize rhizosphere significantly increased in treatments having integrated application of CDBC, green manure and 100% whereas, soil actinomycetes and diazotrophic population were found highest in treatments with sole application of inorganic nitrogen fertilizer. Higher soil microbial populations and enzymatic activities were observed during second year of field study relative to first year. Soil chemical properties viz., electrical conductivity, organic carbon, available nitrogen, available phosphorous and potassium content were found highest under integrated application of CDBC with green manure and recommended dose of nitrogen fertilizer whereas soil pH varied non-significantly among the treatments. Maximum plant height, yield attributes and yield were observed in same treatment. The results indicated that application of CDBC biofertilizer not only decreased the fallow period of green manure decomposition but also enhanced soil health, fertility and yield of maize crop. So, application of CDBC along with green manure and inorganic nitrogen fertilizer can serve as sustainable agricultural practice for maize cultivation.
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    ThesisItemRestricted
    Effect of freeze tolerant baker‟s yeast on dough rising
    (Punjab Agricultural University, Ludhiana, 2018) Jaspreet Kaur; Katyal, Priya
    Among the sophisticated, ready to use frozen products, frozen dough is gaining considerable attention. So, attempt was made to improve freeze tolerance of baker‟s yeast strain by trehalose loading and cold acclimatization and to design its product formulations. Loading with 1.0M trehalose after 7 days of incubation led to increased intracellular trehalose content from 0.3% to 4.71%. Comparative freeze tolerance studies of parent and treated baker‟s yeast revealed that 14 day cold acclimatized culture exhibits maximum cell viability (193cfu/ml) under refrigerated conditions while further incubation for 21 day (167cfu/ml) and 28 day (165cfu/ml) lowered the cell viability. The 28 day cold acclimatized culture showed higher total sugar content of 36.29% followed by 1.0M trehalose loaded culture (29.44%). Maximum trehalose content (4.71%) was shown by 1.0M trehalose loaded culture. Minimum invertase (29.79 nmol/min/ml) and maximum maltase activity (627.99 nmol/min/ml) was shown by 1.0M trehalose loaded culture and 21 day cold acclimatized culture, respectively. Biomass production of baker‟s yeast was carried out at conditions pre-optimized in our laboratory:- pH-6.0, aeration-120 rpm and temperature-30⁰C using unclarified molasses as carbon source and corn steep liquor (CSL) as nitrogen source. Best dough rising ability was shown by 14 day cold acclimatized culture. Product formulation as cream yeast and dried (lyophilized and tray dried) yeast was prepared, out of which cream yeast was used in bread making while nutritional profiling of dried yeast formulations showed the presence of crude protein (23.39-28.98%), crude fat (2.14-2.73%), zinc (7.26-10.13mg/100g), iron (27.54-28.09mg/100g), phosphorus (463.9-593.44mg/100g), calcium (2913.7-5308.38mg/100g), tryptophan (0.71-1.09g/100g protein), methionine (0.73-0.83g/100g protein) and cysteine (0.38-0.4g/100g protein). The present study revealed that cold acclimatization of baker‟s yeast can improve its freeze tolerance. Among the two yeast formulations, cream yeast has been found to be suitable for use in dough rising for bread, while dried yeasts can be exploited as nutritional yeast by further testing for required parameters.
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    ThesisItemOpen Access
    Post harvest processing of Pleurotus florida (Mont.) singer into mushroom soup powder
    (Punjab Agricultural University, Ludhiana, 2017) Jaspreet Kaur; Sodhi, H.S.
    Oyster mushroom is the third largest cultivated mushroom in the market. Pleurotus species are popular and widely cultivated in the world. Pleurotus spp. altogether make up 27% of globally produced cultivated mushrooms. Cultivation of Pleurotus florida is easy and low cost production technology. They can degrade and colonize large variety of lignocellulosic wastes. They can grow within temperature range of 20C to 30C. Pleurotus florida was grown on wheat straw, wheat+paddy straw (1:1) and paddy straw substrate. Maximum yield of (60.12 kg/q dry straw) was observed on wheat straw substrate. Similarly maximum fruit bodies (6870 per/q dry straw) were observed in the bags filled with wheat straw. The average weight of fruit bodies in all the cases ranged between (7.79-8.06gm/f.b‘s). The spawn run was completed between 21±3-25±2 days and pin heads appeared between 25±2-33±3 days with the first harvest made between 28±3-39±2 days. P. florida mushroom could be kept for 2-4 days at ambient temperature and could be stored for 12 days at refrigerator temperature in polyethylene, polypropylene and paper bags. It was observed that mushroom drying increased the shelf life of mushrooms upto three months. Among the three drying temperatures (45C, 55C and 65C), 45C was found best as it resulted in good colour, texture and rehydration ratio. The carbohydrate, protein, fat, fibre and ash of dried mushrooms was ranged between 41.59-42.85%, 27.40-29.54%, 4.21-4.32%, 23.01-23.38%, 8.81-9.03%. Being highly perishable in nature, the fresh Pleurotus mushrooms need to be processed to extend the offseason availability. Mushroom soup powder was one such option for improved shelf life of the mushrooms. Three set of mushroom soup powders; without flavour, lemon flavour, mint flavour were prepared and scored by ten judges on ten hedonic point scale for colour, texture, appearance, aroma, taste and overall acceptability upto six months of storage. Mushroom soup powder without flavour was the most acceptable giving an overall acceptability between 9.20-9.25 followed by mint flavour and lemon flavour soup powder. The moisture content ranged between 5.00- 5.11%. Protein, carbohydrate, fat, fibre and ash ranged between 17.3019.42%, 71.03-77.01%, 2.21-3.12%, 3.42-4.01%, 0.89-1.20%. There was no significant effect of storage on the nutrients of soup powder upto six months at room temperature.
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    ThesisItemRestricted
    Impact of non sustainable factors on soil microflora in rice (Oryzae sativa L.) crop.
    (Punjab Agricultural University, Ludhiana, 2014) Jaspreet Kaur; Gosal, S. K.
    A field experiment was carried out to study the impact of non sustainable factors (green manure and plant density) on soil microbial biomass, soil enzyme activities and NPK of soil in order to achieve environment-friendly agriculture and promote the sustainable development of rice (Oryzae sativa L.) crop. Maximum bacterial population (159 × 108cfu/g of soil), methanotrophic population (176 × 104 cfu/g of soil), actinomycetes population (52.5 × 104cfu/g of soil) and alkaline phosphatase activity (21.9 mg/g of soil/hr) was observed in the treatment having green manure (15t/ha) + 44 plants/m2+ recommended NPK whereas diazotrophic population (57.61 × 105cfu/g of soil), fungal population (25 × 103cfu/g of soil), dehydrogenase activity (50.0 µg TPF/g of soil/hr) and urease activity (855 µg/ g of soil/hr) was observed maximum in treatment with green manure (15t/ha)+33plants/m2+ recommended NPK. Biochemical characterization of 18 different methanotrophic bacteria isolated from rice crop revealed that all isolates were positive for citrate production; negative for indole and VP test whereas most of them were positive for methyl red and negative for H2S production. Maximum soil nitrogen (206.9 Kg/ha) was observed in treatment having green manure (15t/ha) + 33plants/m2+ recommended NPK whereas soil potassium (212.0 Kg/ha) and phosphorus (35.8 Kg/ha) were observed maximum in treatment having green manure (15t/ha) + 44 plants/m2+ recommended NPK. Increased plant height (103.8cm) and yield attributes like effective tiller (386/m2), number of spikelet (18), filled grain panicle-1 (136), thousand grain weight (22.4g), straw yield (86.65 Q/ha) and grain yield (73.25 Q/ha) were observed in same treatment. Significantly positive effects of green manure were observed on microbial biomass, enzyme activity, NPK content and on yield of rice. The results indicated that increase in plant density did not show negative effect on soil fertility and crop yield. So, application of green manure and increasing plant density effectively increase yield and sustainability of rice cropping system.