US private equity firm KKR & Co Inc (<a href="https://www.nyse.com/quote/XNYS:KKR" target="_blank">NYSE:KKR</a>) has agreed to buy an additional 5% stake in Eni SpA’s (<a href="https://www.borsaitaliana.it/borsa/azioni/scheda/IT0003132476.html?lang=en" target="_blank">BIT:ENI</a>) biofuels subsidiary Enilive, investing further EUR 587.5 million (USD 615.3m) in the business.