The deal, concluded at the beginning of the month, included all European GBI activities such as the Bread Improver and Pastry Ingredients subsidiaries and means that the ingredients company will now trade under the name GB Plange UK as part of its move to the Werhahn group.
The merger will bring together two European ingredients giants and add to Werhahn's growing industrial bakery business which announced an annual turnover of €300m (£203.57m) this year.
The company, which is part of the wider Werhahn Group, manufacturers and sells flour, bread and pastry ingredients.
It is the second largest provider of milled products in Germany and has an output of 1.1m tonnes of grain.
GBI claims to be the world's third biggest yeast producer and will continue to operate its profitable yeast business in conjunction with GB Plange UK.
The makers of dry, fresh and other yeasts are based in the Netherlands and have additional production facilities in Germany, Italy, Chile and the UK. Last year, it recorded net sales of around €350m (£237.56m)