(Adds PKN Orlen, Triton)
Jan 30 (Reuters) - The following bids, mergers, acquisitions and disposals were reported by 1430 GMT on Thursday:
** Textbook publishers Cengage Learning Holdings and McGraw-Hill Education, who announced last year that they would merge, have extended their merger agreement to May 1, the companies said on Wednesday, as some countries are still reviewing the deal.
** Guidon Energy, an oil exploration and production company majority-owned by Blackstone Group Inc, is exploring a sale that could value the Permian basin operator at more than $2.5 billion including debt, according to people familiar with the matter.
** Japan's Daiwa Securities Group Inc said it would invest 14 billion yen ($128 million) in a marketing company Katana, aiming to diversify revenue sources as stock transaction fees are expected to shrink.
** Four Saudi aquaculture firms have merged in a 500 million riyal ($133 million) deal, state news agency SPA said.
** PKN Orlen, Poland's biggest oil refiner, does not currently expect to raise its bid for utility Energa , PKN Orlen Deputy Head Patrycja Klarecka said.
** Triton has emerged as a front runner to clinch the purchase of Volkswagen's transmissions unit Renk, a source familiar with the matter told Reuters. (Compiled by Arundhati Sarakar in Bengaluru)