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Please use this identifier to cite or link to this item: http://lrcdrs.bennett.edu.in:80/handle/123456789/2118
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dc.contributor.authorSharma, Sumit-
dc.date.accessioned2024-04-22T11:10:54Z-
dc.date.available2024-04-22T11:10:54Z-
dc.date.issued2023-
dc.identifier.urihttp://lrcdrs.bennett.edu.in:80/handle/123456789/2118-
dc.description.abstractLignin is a complex polymer of aromatics and a part of lignocellulosic biomass. Several paper/pulp industries and biorefineries are producing a huge amount of lignin as a by-product and still facing challenges for its management and further use. This study relates to the utilization of lignin to improve its importance in process development. Castor is a renewable non-edible source of long-chain hydrocarbons. India contributes nearly 80% of castor oil around the world. It is mainly exported from India at a very low price of 1.62-15.21 USD/kg. There are very few indigenous technologies of castor oil processing into value-added products and mostly depends on chemical catalysis which is usually non-sustainable. For this study, a new strain of Aspergillus flavus BU20S was isolated and identified by sequence analysis of ribosomal internal transcribed spacer (ITS) regions and cyp51A gene. An unknown metabolite produced by the strain was identified by elucidation of molecular structure using a combination of 13C and 1H-NMR, MS, FTIR, XRD, UV, and HPLC analysis. The metabolite was found to be kojic acid, which showed the potential to treat methicillin-resistant Staphylococcus aureus (MRSA) infection, among other industrial applications. It was observed that the isolated strain can produce kojic acid from castor oil and product titer can be increased by supplementing the medium with rice straw-derived depolymerized lignin. The substrate concentrations were optimized by response surface methodology using Design-Expert® software. As high as 6.69 ± 0.24 g/L of kojic acid was obtained using castor oil (20 g/L) and depolymerized rice straw lignin (3 g/L). For the first time, kojic acid has been reported from castor oil in this study. Kojic acid titer was also enhanced by a sequential fed-batch strategy. There was a 2 times increase in the product when sequential feeding was executed. Along with that, the effect on nitrogen source, C/N ratio was also studied. A 3.63-times increase in the kojic acid (4.43 ± 0.47 g/L) was found when only the ammonium chloride was supplemented in glucose (10 g/L) medium than all minimal salts. The molecular carbon/nitrogen ratio (C/N) was found optimal at 23.58 which gives a high titer of 5.17 ± 0.84 g/L from 10 g/L of glucose. At this optimal molecular nitrogen value, the nitrogen supplement cost can be reduced by 99% compared to yeast extract. The antimicrobial activity of purified kojic acid showed a ~20 mm zone of inhibition at a 2.5 mg dose loaded over 7.4 × 109 CFU/mL of MRSA. Compared to the control, around 85% decrease in cellular growth of MRSA was observed when kojic acid (10 mg/mL) was supplemented at initial Absorbance600nm of 0.03.en_US
dc.language.isoen_USen_US
dc.publisherBennett universityen_US
dc.subjectBiotechnologyen_US
dc.titleUtilization of lignin in kojic acid production by a newly isolated strain of aspergillus and also in removal of industrial dyeen_US
dc.typeThesisen_US
Appears in Collections:School of Engineering and Applied Sciences (SEAS)

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