* Offers NOK 13.5 vs NOK 12.5
* Deadline remains Friday
* Share jumps, trades just below offer price (Adds details, share price)
OSLO, Jan 15 (Reuters) - Germany's BASF lifted its offer for Norwegian fish oils maker Pronova on Tuesday after its initial offer failed to attract enough acceptances.
BASF lifted the bid to 13.50 crowns per share, valuing the firm at $737 million after its 12.5 crowns offer got acceptances from just 69.7 percent, below its 90 percent threshold, Pronova said in a statement.
BASF wants to boost its nutrition business and capitalise on the Norwegian firm's expertise in the extraction of omega-3 fatty acids from fish oil for use in drugs and food supplements.
Pronova shares jumped on the new offer but traded just below the 13.50 crown offer price, indicating that the new bid has a much better chance of succeeding.
Shareholders had been lukewarm about the initial offer, saying it undervalued the firm and offered just a modest 4 percent premium compared to the stock's last close before the bid.
Two shareholders, Odin Forvaltning and Handelsbanken Asset Management, who hold about 5 percent of Pronova had already rejected the offer.
Pronova, in addition to previous acquisitions of consumer product groups Cognis and Equateq, would help BASF cover the entire omega-3 range from food-grade to highly concentrated versions for drugs in a market where its competitors include DSM and Croda.
Shareholders have until 1530 GMT on Friday to accept the offer. ($1 = 5.5103 Norwegian krones) (Reporting by Balazs Koranyi and Ludwig Burger; Editing by Greg Mahlich)