Dec 28 (Reuters) - Sustainable food processing firm Darling Ingredients Inc (DAR.N) said on Tuesday it had agreed to buy Valley Proteins Inc, a startup focused on collection and recycling of waste,for about $1.1 billion in an all-cash deal. The acquisition will provide Darling Ingredients with additional low-carbon feedstock to produce renewable diesel and potentially sustainable aviation fuel, the company said. Darling Ingredients is a producer of renewable clean energy and collects waste streams from the agri-food industry, repurposed into specialty ingredients including animal proteins and meals, plasma, pet food and green bioenergy. Climate awareness and investor interest in sustainable business practices have surged this year, with companies and investors looking to factor in environmental social governance (ESG) policies. Earlier this month, packaging products provider Sonoco Products Co (SON.N) said it would buy sustainable metal packaging maker Ball Metalpack for $1.35 billion to expand its sustainable packing portfolio. read more