The term job satisfaction can mean a number of things to different people but in my experience one thing is clear, without satisfaction, there can be no such thing as a motivated employee.
First let's agree that companies are in business to make money! Second the most important ingredient in that equation is the employees, that is why so much time an money is spent recruiting and searching for the good ones so they can be trained and start producing.
This equation falls apart if they have no satisfaction in their job. They may have the greatest incentive package in the world but if that employee does not have job satisfaction, then those incentives are meaningless.
There are a number of theories about this topic but most can be categorized in one of three elements; salary, security and work conditions.
The best way to understand this is to look at yourself. If you are not making enough money, no matter how much you love you job at some point it will cause stress because you won't be able to pay your bills or have the life you want.
Same goes for security and work conditions. If you go into work every day not knowing if you will be fired, or to a place of work where the work conditions are such that people are always yelling at you and each other or people are getting fired and replaced all the time, it will cause stress.
So the job satisfaction comes down to the elements of a job that if they are not in place can distract an employee from performing a their best.
As a manager or HR professional, it is your job to make sure these elements are in place at your company. The benefits easily outweigh the costs. Firing, debriefing, recruiting, interviewing, onboarding, and training a new person over and over is a costly ordeal and saps productivity.
To enable satisfaction each of the elements must be addressed. It will not come overnight but it is important for employees that each is given attention and real change being if they are not all in place.
If you have no idea where to start, hire a professional who can do surveys and interviews with your employees. There are a number of professional who specialize in employee motivation and it starts with satisfaction. Most will tailor a program to fit your budget and the biggest benefit is what I call business myopia. Sometimes it takes an outsider to see the real problem. When you are too close to the problem it is easy to look past it.
Start with recommendations. Failing that do some research. There are other terms besides employee satisfaction. It comes under the concept of workforce management. There are trainers and business consultants that specialized in dealing with these types of issues. Most will work with you at whatever level you can afford and remember it is a great deal cheaper to keep than to replace!