ADAPTIVE LABORATORY EVOLUTION STRATEGY FOR IMPROVEMENT OF GROWTH AND SUBSTRATE UTILIZATION OF BACILLUS SUBTILIS IN HAZELNUT SHELLS HYDROLYSATE

Date

2023-7-21

Author

Tukur, Ummulkhairi

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Lignocellulosic materials are worldwide naturally abundant. Similarly, due to industrial processing, hazelnut shells are enormous in Turkey. Utilizing them for various purposes, including bioprocess, reduces environmental pollution and improves bio-economy. Microbial fermentation inhibitors formed during pre-treatment of lignocellulose material to release fermentable sugars is a challenge for bioprocessing. The most promising strategy to tackle this problem is biological detoxification. This study aimed to use the method of adaptive laboratory evolution for improving the growth rate and substrate consumption of Bacillus subtilis in hazelnut shells hydrolysate under various cultivation conditions of pH (5,6, and 7) and inoculum ratio (2,5, and 10%). Dry weight of biomass was used to monitor the growth rate improvement. The substrate consumption was measured spectrophotometrically using the DNS method. The results were statistically analyzed by One-way Analysis of variance (ANOVA) for the biomass produced and Kruskal Walli's nonparametric test for the daily substrate consumption. The results showed that the best condition for biomass production was found at pH 7 and 10% inoculum ratio with 6.17±0.07 g/L biomass produced and the residual sugar of 15.04 ± 0.12g/L. Poor adaptation was observed at pH 5 with an inoculum vi ratio of 2%. The result shows the potential to improve the growth and sugar consumption of B.subtilis. Overall, biomass increases with an increase in pH for different inoculum ratios, with pH 7 having higher biomass than other pHs.

Subject Keywords

Hydrolysate, Bacillus subtilis, Evolutionary Adaptation, DNS method, Statistical analysis

URI

https://hdl.handle.net/11511/104909

Collections

Graduate School of Natural and Applied Sciences, Thesis