Isolation and characterization of amylolytic, cellulolytic, or proteolytic bacteria from the rumen of a native Philippine carabao (Bubalus bubalis L.)

Date

4-2010

Degree

Bachelor of Science in Biology

Major Course

Major in Microbiology

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Noel G. Sabino

Request Access

To request access of this material, please email the administrator at uscs-mainlib.uplb@up.edu.ph

Abstract

Solid and liquid samples were taken from the rumen of a native Philippine carabao in the Department of Animal Science, UPLB. From these samples, a total of 26 bacterial isolates were obtained. All isolates were Gram-positive; four were bacilli in form, while all the rest are coccoid. Moreover, all isolates were catalase-negative and all were aerotolerant anaerobe, except for a single facultative anaerobe. All the isolates were screened for amylolytic, proteolytic and cellulolytic activity using Thioglycollate-Salts Medium supplemented with either starch, skimmed milk and cellulose. Of the 26 isolates, none exhibited amylolytic activity but four isolates scored positive for proteolysis; of these four, Isolate AS1 gave the numerically widest zone of clearing (13.33mm). Moreover, 14 isolates exhibited cellulolytic activity; of these 14, Isolate AS1 gave the numerically widest zone of clearing (4.67 mm). It was interesting to note that three of the four isolates that exhibited proteolytic activity were also cellulolytic. This isolate, along with Isolate BS7, were subjected to quantitative screening of cellulase activity. Cellulase activity was quantified using the DNS (3, 5-dinitrosalicylic acid) method. Absorbance readings of the test samples containing cell-free extracts of the isolates were obtained and compared against a glucose solution standard curve. The amount of reducing sugars released from the action of the cell-free extracts on carboxymethylcellulose, which was the reaction substrate, was then computed. A computed value of 0.1 mg glucose/0.5 ml was obtained for Isolate AS1 while 0.34 mg glucose/0.5ml was computed for BS7. This indicates that Isolate BS7 actually produced more reducing sugars after the 30-minute reaction time as opposed to Isolate AS1. Furthermore, selected isolates, namely Isolates AS1, AL2, AS4 and BS7 were characterized using API 20 A system. Results from the biochemical tests suggested that AL2 and AS4 were identical, if not the same organism. However, numerical profiles obtained from the test found no match in the API database. Nonetheless, the possible identities of the characterized isolates were determined by making referral to the Bergey’s Manual of Systematic Bacteriology. Isolate AS1 is possibly under the genus Eubacterium while AL2, AS4 and BS7 are under the family Streptococcaceae.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Document Type

Thesis

This document is currently not available here.

Share

COinS