Screening and optimization of conditions for xylanase production from bacterial isolates

Date

4-2004

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Teresita M. Espino

Abstract

San Gabriel, Elgin Vigilia, College of Arts and Sciences, University of the Philippines Los Banos, April 2004. Screening and Optimization of Conditions for xylanase Production from Bacterial Isolates

Adviser: Dr. Teresita M. Espino

Co-adviser: Dr. Maxima E. Flavier

Seventy-one (71) unknown mangrove isolates and 10 identified bacterial isolates all from Philippine National Collection of Microorganisms (PNCM), National institute of Molecular Biology and Biotechnology (BIOTECH), UP Los Banos were screened for xylanase activity.

Four bacterial cultures specifically Bacillus subtilis BIOTECH 1332, Bacillus amyloliquefaciens BIOTECH 1583, and unknown mangrove isolates U-124 and U-133 were selected for optimization studies. Unknown bacterial isolates were partially characterized. Isolate U-124 belongs to the genus Bacillus while U-133 may belong to Pseudomnas or Azotobacter genera. Further tests should be done to accurately identify U-133.

Four types of media at pH 7.0 were tested for bacterial xylanase production. Three sources of xylan namely rice bran, commercial wheat bran (Polard), and milled wheat bran were simultaneously tested. Each organism tested showed specific medium preference and source of xylan for xylanase production. The optimum inoculation level for the four selected bacterial cultures was 10% (108CFU/rnL). Mangrove isolates U-124 and U-133, together with B. subtili.s. 1332 produced the highest xylanase activity at pH 7.0, while B. amyloliquefaciens 1583 has an optimum pH of 5.0. The optimum temperature for xylanase production by U-124, B. suhtilis 1332, and B. amyloliquefacien• 1583 was 30°C, while for U-133, 34°C. The optimum incubation time for B. subtilis 1332 and U-133 was 24 h, while for B. ainyloliquefaciens 1583 and U-124, 48 h. Bacillus sublilis 1332 produced the highest xylanase activity (9.9 XAU/mg protein) in 0 5% (w/v) Polard, while B. amyloliquefacien.s. 1583 produced its highest xylanase activity (16.2 XAU/tng protein) in 1.5% (w/v) milled wheat bran. Highest xylanase activities (1.7 XAU/mg protein and 2.1 XAU/mg protein respectively) for mangrove isolates U-124 and U-133 were recorded from 2.0% (w/v) milled wheat bran.

Comparison of optimized and unoptimized conditions showed no significant increase in xylanase activities for mangrove isolates U-124 and U-133. Significant increases in xylanase activities were observed for B. subtilis 1332 and 13. cuitylohquefaciens 1583 representing 2.51 and 1.16 fold increases using the optimized conditions

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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