Chapter 28, Problem 1RC

Summary Introduction

To determine: The effect of nutrient availability and environmental factors on microbial growth.

Introduction: The microbes can be divided into different types. For example, the unicellular microbes that form a major part of prokaryotes are termed as bacteria. They can live in a variety of habits such as air and soil.

Explanation of Solution

There are different nutrients essential for the growth of microorganisms. For example: iron is one of the nutrients that are essential for the various energy-conserving processes. The following are the environmental factors affecting microbial growth:

• pH: pH is referred to as the comparative acidity of a particular solution. The different microbes have different pH range that is optimum for their growth. For example, acidophiles can be found at the place having pH range 0 to 5.5.
• Temperature: Most of the microbes do not have the ability to survive at high temperature. This is because most of the enzymes are sensitive to high temperature and get denatured.
• Oxygen concentration: The concentration of oxygen indicates about the ability of an organism to converse energy that is required for various metabolic processes. Most of the microbes cannot live in the absence of oxygen. However, some organisms are called facultative anaerobes that can survive in absence of oxygen but show high growth rate in the presence of oxygen.
• Pressure: The terrestrial organisms mainly survive at 1 atmospheric pressure. However, some organisms that are known as piezophile can survive at atmospheric pressure higher than 1 atm.
• Radiation: The primary source of radiation on the planet Earth is sunlight that comprises ultraviolet radiation, radio waves, infrared rays, and visible light. One of the most damaging forms of radiation is ultraviolet radiation. These radiations may influence the growth of microbes.