Jacques Maman, corporate marketing manager for Galam, said the synergy is aimed at developing more natural sweeteners for use in dairy, beverages and bakery products and extending the market base of the two companies.
It is not set to affect supplies or price to current customers of either company.
Until now, Atomer has only sold its liquid fructose and liquid sugars to Spain, but now plans to extend its sales further.
It will concentrate its activities in Southern France, Italy and Portugal.
Atomer will also focus on ensuring its liquid sweeteners are natural products, with no genetic modification.
Galam claims to be the leading supplier of non-GMO Crystalline Fructose in Europe as well as having a growing worldwide market.
It now wants to become one of the leaders in the global crystalline and liquid fructose market.
In 2004, Galam already set up Eurosweet, a liquid sweeteners production unit in Germany that provides liquid sweet blends for the food and beverage industries.
It hopes the investment in Atomer SL will reinforce Galam Group presence in Europe in the liquid blends market.
Fructose is a simple sugar (monosaccharide) found mainly in honey, tree fruits, berries, melons, and some root vegetables.
The two companies are confident there will be sufficient market demand for their increased fructose production.
Maman told FoodNavigator.com: "The market is continuously growing, especially in soft drinks and dairy.
The market is looking for a natural sweetener with low GI and low calorie count."
The GI measures how quickly certain foods release carbohydrates into the body, which then raise consumers' blood glucose levels.
High GI foods cause blood sugar levels to rise more rapidly.
Therefore, because of its low GI, fructose has been recommended as an alternative to sugar for people with diabetes mellitus or hypoglycaemia.