Master of Science
Nguyen Hoang Kim Nuong
Department of Earth and Environmental Sciences, National Chung Cheng University, Taiwan
Title: Optimal cellulase production and rice straw degradation by Bacillus subtilis S1-7 isolated from mangrove sediment at Puzi River mouth, Chiayi county, Taiwan
Name(s): Nguyen Hoang Kim Nuong and Chien-Yen Chen
Cellulolytic bacteria play a vital role in decomposing plant-derived cellulose into simple sugars and nutrients, supporting ecosystem functions in mangrove sediments. This study aimed to isolate and identify high-potential cellulolytic bacteria from mangrove sediment at the Puzi River estuary, Chiayi County, Taiwan, and to evaluate their potential in agricultural residue degradation and plant growth promotion under saline conditions. The most effective isolate was identified as Bacillus subtilis S1-7 and used for optimization of growth, cellulase production, and rice straw degradation. Optimal conditions (2% inoculum, 10 g/L NaCl, 0.085 g/L MnSO₄·4H₂O, 10 g/L CMC or rice straw powder, and 0.5 g/L each of (NH₄)₂SO₄ and yeast extract) resulted in high bacterial density (9.03 log(CFU/mL)) and elevated endoglucanase and exoglucanase activities (0.503 and 0.540 U/mL). FTIR spectra revealed decreases in hemicellulose- and cellulose-related functional groups, while XRD analysis showed changes in crystallinity, confirming structural breakdown of rice straw. Under optimized conditions, B. subtilis S1-7 achieved substantial degradation, producing 1003 mg/L glucose with a final density of 8.76 log(CFU/mL). These results demonstrate the strain’s strong potential for enhancing agricultural residue conversion and supporting sustainable practices in saline environments.
Biography of the presenting author
Nguyen Hoang Kim Nuong is a PhD student in the Department of Earth and Environmental Sciences at National Chung Cheng University, Taiwan. She also is a researcher in the Department of Soil Science at Can Tho University, Vietnam. Her research focuses on cellulolytic bacteria and their application in rice straw degradation under saline conditions. She also works on rice growth promotion using phosphate-solubilizing bacteria and indole-3-acetic acid (IAA) production to enhance plant performance in salt-affected environments. Her current work aims to identify and apply high-potential bacterial strains to support sustainable agriculture in regions such as the Mekong Delta, Vietnam.
Presenting author details
Full name: Nguyen Hoang Kim Nuong
Contact number: 0987 379843
Email: nhknuong@ctu.edu.vn
Session name/ number: Agricultural Biotechnology
Category: Oral presentation/ Poster presentation