PG AND RESEARCH DEPARTMENT OF MICROBIOLOGY,SRI PARAMAKALYANI COLLEGE ALWARKURICHI.

1. SRI PARAMAKALYANI COLLEGE
(REACCREDITED WITH B GRADE WITH A CGPA OF 2.71 IN THE II CYCLE BY NACC
AFFILIATED TO MANONMANIAM SUNDARANAR UNIVERSITY,THIRUNELVELI)
ALWARKURICHI -627 412 TAMILNADU INDIA.
POSTGRADUATE& RESEARCHCENTER– DEPARTMENTOFMICROBIOLOGY
(GOVERMENTAIDED)
I SEM - CORE – MICROBIAL PHYSIOLOGY
UNIT – 4
NITROGEN FIXATION & NIF GENE
SUBMITTED TO
THE GUIDE
DR.S.VISWANATHAN,PH.D
HEAD OF THE DEPARTMENT
SRI PARAMAKALYANI COLLEGE
ALWARKURICHI.
SUBMITTED BY
M.MOHAMED FAISEL
REG.NO : 20211231516114
I M.SC, MICROBIOLOGY
DATE: 06.12.2021

2. SYNOPSIS
Introduction
Nitrogen fixation
Symbiotic N2 fixation
Root noodule formation
Asymbiotic N2 fixation
Nitrogenous complexes
Nif gene
Reference

11. Nifgenes
• The complex of genes encoding enzymes involved in the fixation of
atmospheric nitrogen.
• They are found in nitrogen-fixing bacteria. They occur as an operon in free-
living anaerobic nitrogen-fixing bacteria such as Klebsiella pneumoniae,
Rhodospirillum rubrum, and Rhodobacter capsulatus.
• The nif genes are genes encoding enzymes involved in the fixation of
atmospheric nitrogen into a form of nitrogen available to living organisms.
nif genes also encode a number of regulatory proteins involved in nitrogen
fixation.
• The nif genes are found in both free-living nitrogen-fixing bacteria and in
symbiotic bacteria associated with various plants.
• The nif genes are found in both free-living nitrogen-fixing bacteria and in
symbiotic bacteria associated with various plants.

13. REGULATION
• In most bacteria, regulation of nif genes transcription is done by
the nitrogen sensitive NifA protein.
• If there is a sufficient amount of reduced nitrogen or oxygen is
present, another protein is activated.

15. REFERENCE
https://byjus.com/biology/nitrogen-fixation-nitrogen-metabolism/
https://www.sciencedirect.com/topics/agricultural-and-biological-
sciences/nitrogen-fixation
https://courses.lumenlearning.com/boundless
microbiology/chapter/nitrogen-fixation
https://collegedunia.com/exams/nitrogen-fixation-definition-types-and-
process-biology-articleid-1861

18. THANKS TO
• The Chairman
• The Secretary
• Management Committee
• The Principal of Sri Paramakalyani College
• The Head - Department of Microbiology
• The Staff Members - Department of Microbiology