Isolation and identification of nitrogen-fixing bacteria and screening for growth enhancement of yellow and super sweet corn

Date

4-2013

Degree

Bachelor of Science in Biology

Major Course

Major in Microbiology

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Nacita B. Lantican

Abstract

A total of 88 N2-fixers were isolated from various farm areas in the Philippines planted with Zea mays. Acetylene Reduction Assay was used to screen for high nitrogen-fixing isolates. The isolates GH63, CG82.2, DH7, DG70.1, CE33.2b and DB1 had the highest rate of acetylene reduction ranging from 1,664.82 - 3, 101.33 nmol C2H4 per Lhr. The effectiveness of the microbial innoculants were verified through two pot trials using Yelo corn cv IPB Var 13 and Super sweet corn as host plants and grown for 10 days in field collected soil and pasteurized field soil. Microbial innoculation gave significant increases over the uninoculated control shoot biomass, shoot and root length of yellow corn in unpasteurized soil; inoxulation with Bio-N gave the highest values, Moreover in terms of nitrogen content and uptake, greater amounts were observed in plants inoculated with the isolates, suggestive of improved nitrogen nutrition. Morphological, biochemical, and molecular characterization succesfully identified the microbial isolates to be members of the genus Enterobacter, Klebsiella pneumoniae and Providencia stuartii. This study reported on the diaztrophic nature of Providencia stuartii despite the absence of nif genes (coding for nitrogenase) in the sequenced genome suggestive of other means of nitrogenase activity. Further activity is needed to explore this novel trait.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 2013 B4 A68

Document Type

Thesis

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