Germany's Symrise is buying Pinova Holdings, a U.S. maker of perfume ingredients from natural sources, for at least $397 million from buyout firm TorQuest, part of a push into plant-based ingredients for its fragrances and flavors.

Symrise has a focus on plant-based substances, which are preferred by many consumer goods makers over petrochemical-based ingredients. The company expanded into ingredients businesses to have a better control over manufacturing practices.

The deal reflects "the increasing importance of natural and renewable raw materials for the fragrance industry," Symrise Chief Executive Heinz-Juergen Bertram said on Monday.

Pinova was created in 2010 when TorQuest acquired Ashland's refined wood rosin and natural wood terpenes unit and combined it later with LyondellBasell's Flavors & Fragrances business, now called Renessenz.

The price tag amounts to as much as 11.1 times Pinova's 2014 adjusted earnings before interest, taxes, depreciation and amortization (EBITDA) of $37.4 million. That compares with a multiple of 17.3 that Symrise is trading at, 12.7 for rival IFF or 17.2 times for Switzerland's Givaudan , another competitor.

Subject to conditions to be met within 12 months, Canada's TorQuest will receive a premium of $20 million for a total price of up to $417 million.

The buyer's stock extended gains and was up 2.1 percent at 1158 GMT.

Symrise expects annual synergy effects worth 20 million euros ($22.6 million) from the deal by 2020.