Thumbnail Image

Thesis

Browse

2012 - 20203
Reset filters
Subject: Microbiology × Author: Avneet Kaur × End date: 2020 × Thesis Type: M.Sc ×
Reset filters

Search Results

Now showing 1 - 3 of 3
  • Thumbnail Image
    ThesisItemOpen Access
    Bioutilization of spent mushroom compost for remediation of heavy metal rich effluents
    (Punjab Agricultural University, Ludhiana, 2020) Avneet Kaur; Katyal, Priya
    The present study was conducted to use spent mushroom compost (SMC) as a low cost effective biosorbent combining the advantage of biosorption and bioaccumulation approach for remediation of heavy metal rich effluents. Effluent samples were collected from two Common Effluent Treatment Plants (CETPs) located at Ludhiana (L-CETP) and Jalandhar (JCETP). Samples were analysed for various physico-chemical parameters, whereby DO (43.92 mg/l) and BOD values (13.2 mg/l) were low in L-CETP whereas COD value (320 mg/l) was higher than permissible limit (250 mg/l) indicating that sample was polluted with organic contaminants. In J-CETP, DO (92.0 mg/l) and BOD (71.5 mg/l) values were high while COD value was low (240 mg/l) indicating that sample has indigenous microflora. Total solids (TS) and Total dissolved solids (TDS) were found to be high in J-CETP. Metal profile of effluent samples was estimated using Inductively Coupled Argon Plasma-Atomic Emission Spectroscopy (ICAP-AES). In Ludhiana CETP, Cr was dominant heavy metal with a concentration of 226.62 ppm, followed by Ni 28.12 ppm and Pb 0.77 ppm. In Jalandhar CETP, the concentration of Cr was 1.83 ppm, followed by Pb 0.39 ppm and Ni 0.10 ppm. Heavy metal tolerance was determined by growing cultures of Pleurotus florida, Agaricus bisporus, Volvariella volvacea and Calocybe indica in Potato Dextrose Agar (PDA) plates amended with heavy metals. Cultures of white rot fungi were most sensitive to Hg and least sensitive to Cr. Among the four selected strains, Volvariella volvacea was found to be highly resistant to Cr with 22.5% inhibition of growth at 250 ppm. SMC of selected white rot fungi was dried, grinded and analysed for various physico-chemical parameters whereby low values of cellulose, hemicellulose and lignin indicated their degradation during the process of composting and mushroom growth. Batch experiments were carried out in erlenmeyer flasks to study the effect of various parameters like pH, temperature and initial metal concentration on biosorption. Maximum removal of Cr was obtained at Ci-50 mg/l, pH-4-6 and temperature-25°C. Experimental results were well fitted to Langmuir isotherm than to Freundlich isotherm. These standardized conditions were used to study metal uptake from effluent samples by SMC packed in a bioreactor. Maximum removal of Cr was achieved with contact time of 2 hrs with A. bisporus SMC, 3hrs for P. florida SMC and 1.5 hrs for C. indica SMC. FT-IR spectrum analysis of SMC showed shift in peaks at 2918 cm-1 to 2980 cm-1 due to stretching of CH and CH2 group, 1744.7 cm-1 to 1739.6 cm-1 because of masking of protonated carboxyl group and peak at 1500 cm-1 showed the presence of lignin group in treated and untreated spent compost.
  • Thumbnail Image
    ThesisItemOpen Access
    Microbial production of tannase using agro waste
    (Punjab Agricultural University, Ludhiana, 2018) Avneet Kaur; Katyal, Priya
    Tannase (tannin acyl hydrolase, E.C.3.1.1.20) is an inducible enzyme that has wide applications in different food and feed industries including production of beverages, cosmetic chemicals and in clarification of beer and fruit juice. It has also been used for bioremediation of tannins from effluents of leather industries. Attempt was made for isolation of tannase producing microbes (bacteria/fungi) from tannery effluents using tannic acid supplemented media. On the basis of qualitative (zone of hydrolysis) assay, four fungal isolates – AV1, AV2, AV3 and AV4 were found to be more efficient than bacterial isolates for tannase production and the maximum zone was shown by AV3 isolate i.e. 2.3 cm. For the morphological characterization of fungal isolates, lactophenol cotton blue staining and Scanning Electron Microscopy were done. Isolate AV1, AV2, AV3 and AV4 were found to show morphological similarities to genera Penicillium, Fusarium, Aspergillus and Trichoderma, respectively. Quantitative tannase production by the selected four isolates (AV1, AV2, AV3 and AV4) for seven consecutive days revealed AV3 to be the maximum tannase producer (25.33 U/ml) on 5th day of incubation. Four different agrowastes i.e. spent tea powder, coconut coir, corn husk and fruit baggase were used as substrates for tannase production using selected isolate AV3 and the maximum tannase production (35.62 U/ml) was obtained using spent tea powder as substrate at pH 5.5 and temperature 40oC. Optimization of process parameters for maximum tannase activity with central composite design using response surface methodology reveals maximum tannin hydrolysis (93.33µMmin-1) at a temperature of 600C, pH 8.0 and 5% substrate concentration. On partial purification, by ammonium sulphate precipitation followed by dialysis using membrane-70, activity of the tannase increased to 153.33µMmin-1 and the yield of the enzyme was 83.33%. Partially purified enzyme was used for detannification of pomegranate juice and was found to reduce tannin content from 2.76 mg/ml to 1.03 mg/ml but with slight decolorization of juice.
  • Thumbnail Image
    ThesisItemOpen Access
    STUDIES ON BIODEGRADATION OF ENDOSULFAN BY BACTERIAL SPECIES FROM AGRICULTURAL SOILS.
    (Punjab Agricultural University, Ludhiana, 2012) Avneet Kaur
    For bioremediation of endosulfan, nine bacterial species isolated from sugarcane field soils and identified using 16S rDNA sequence homology. These could cause only partial endosulfan metabolization (maximum of 50.22%) coupled with appearance of toxic endosulfan sulphate as metabolite. Evaluation of earlier identified 15 bacterial species resulted in selection of Brevibacterium frigoritolerans, Bacillus alkalinitrilicus and Pseudomonas fulva causing 86.58, 81.30 and 71.58 % endosulfan reduction, respectively. These bacterial species could grow over a wide range of pH (4.0-11.0) and temperature (25-37°C), but optimally at pH of 6.0-6.5 and 37°C, though growth was more rapid in shake than stationary cultures. However, whereas, B. frigoritolerans was sensitive to high salt concentrations, P. fulva & B. alkalinitrilicus grew optimally at salt concentration of 3.0 and 4.0 %, respectively. Maximum endosulfan degradation by B. frigoritolerans and P. fulva was not affected by presence of additional carbon and/or nitrogen sources suggesting the endosulfan metabolization by these species to be inducible by endosulfan only. In case of B. alkalinitrilicus, improvement in endosulfan reduction by the presence of additional C and/or N sources (80.58 to 95.14%) established the constitutive nature of endosulfan degradation. Whereas B. alkalinitrilicus holds potential for bioremediation of endosulfan in nutrient enriched agricultural soils and sewage water, B. frigoritolerans and P. fulva could find equal exploitation for endosulfan degradation in nutrient deficit environments.