Accel-KKR has agreed to acquire Sumtotal Systems Inc. (Nasdaq: SUMT), a Mountain View, Calif.-based provider of enterprise learning and performance management systems. The $3.80 per share offer would value Sumtotal at roughly $124 million, and tops a $3.25 per share bid made by Vista Equity Partners earlier this month.

AIG has received three bids for its aircraft leasing business, with each one coming in at under $5 billion. The unit’s book value was $7.6 billion at the end of 2008. Terra Firma Capital Partners is leading one bid, while the others are: The Carlyle Group/THL Partners and Onex Partners/Greenbriar Equity.

Apollo Global Inc., the parent company of University of Phoenix, has offered to buy UK education and training company BPP Holdings PLC (LSE: BPP) for approximately $447 million. The deal valued BPP shares at a 70 percent premium when it was announced. The Carlyle Group holds a 19.9 percent stake in Apollo Global.

Ashland Inc. (NYSE: ASH) has put its Valvoline motor oil division on the block, according to The New York Post. The sale could garner Ashland upwards of $1 billion.

Bain Capital and Kohlberg Kravis Roberts & Co. reportedly are considering separate bids for around a 20 percent stake in Chinese electronics retailer GOME (HK: 0493). The deal was worth around $385 million based on recent trading prices, with existing GOME shareholder Warburg Pincus also reported to have interest.

The Blackstone Group has joined an investor consortium that plans to bid for troubled BankUnited Financial Corp., according to Dow Jones. As previously reported, the group also includes WL Ross & Co. and The Carlyle Group.

ComVest has agreed to acquire NationsHealth Inc. (OTC BB: NHRXE), a Sunrise, Fla.-based home delivery provider of diabetes supplies, insulin pumps, medications and other medical products. The deal is valued at approximately $3.4 million.

Crunch, a New York-based fitness club chain, has agreed to be acquired by its senior secured lenders, Angelo, Gordon & Co. and New Evolution Fitness Co. The acquisition will occur via a voluntary, pre-packaged Chapter 11 bankruptcy process that allows other interested parties to submit buyout bids.

Energy Future Holdings Corp. (f.k.a. TXU) reported a $442 million Q1 profit, compared to a $1.3 billion loss over the same time period last year. The company was taken private in late 2007 for $44 billion by Kohlberg Kravis Roberts & Co., GS Capital Partners and TPG Capital.

Energy Investors Funds has acquired Watertown Renewable Power LLC, a 30-megawatt biomass power project currently under development in Watertown, Connecticut. The seller was Tamarack Energy Inc. No financial terms were disclosed.

Enesco LLC, a giftware platform sponsored by Tinicum Capital Partners, has agreed to acquire the Charming Trails brand of resin figurines from Fitz and Floyd Inc. It also has acquired the Department 56 brand from Lenox Group Inc. (recently acquired by Clarion Capital Partners), according to LBO Wire. No financial terms for either transaction were disclosed.

The Gores Group has acquired a 51 percent stake in Stock Building Supply Holdings LLC,a Raleigh, N.C.-based supplier of building products to professional builders and contractors, from Wolseley PLC. The deal is conditioned on the completion of a pre-packaged Chapter 11 process that is expected to last between 45 and 60 days. At that point, Gores would invest $75 million and provide a $125 million revolving credit bridge facility. Wolesley would retain a 49 percentr ownership interest.

Irving Place Capital and Oaktree Capital Management have completed their acquisition of Richmond, Va.-based Chesapeake Corp., a bankrupt maker of paperboard and plastic packaging. The deal was valued at $485 million.

Kohlberg Kravis Roberts & Co. is finalizing an agreement to buy South Korean-based Oriental Brewery from InBev for around $1.8 billion.

Lincoln Educational Services Corp. (Nasdaq: LINC) has completed its $2.8 million acquisition of Clemens College, a provider of associate programs in hospitality management. Lincoln Educational is majority-owned by Stonington Capital.

LLR Partners has agreed to acquire I-many (Nasdaq: IMNY), an Edison, N.J.-based provider of enterprise contract management software and services. Under terms of the agreement, I-many stockholders would receive $0.43 per share in cash, for a transaction value of approximately $36 million (or $23.3 million net of I-many’s debt and transaction-related expenses).

Mid Europa Partners has agreed to acquire UPC Slovenia, a Slovenian cable and broadband operator, from Liberty Global Inc. No financial terms were disclosed.

Milestone Partners has sponsored the recapitalization of Blaschak Coal Corp., a Mahanoy City, Penn.-based miner, preparer and marketer of anthracite coal. No financial terms were disclosed. Harris Williams & Co. advised Blaschak on the deal.

Monomoy Capital Partners has acquired Global Thermoplastics LP, a Houston, Texas-based maker of engineered compounds for plastic molding applications. No financial terms were disclosed. Monomoy will merge Global Thermoplastics into Fortis Plastics LLC, a plastic injection molding and extrusion platform that the firm formed late last year.

Olympus Partners has invested $50 million in equity and subordinated debt in the parent company of Phoenix Services LLC, a Unionville, Penn.-based provider of mill services to the steel industry.

Performance Designed Products LLC, a maker of video game accessories, has sued Dreamgear LLC for patent infringement and trade dress infringement. PDP is a portfolio company of Patriarch Partners.

Platinum Equity has completed its acquisition of The San Diego Union-Tribune newspaper from The Copley Press Inc. The all-equity deal reportedly was worth less than $50 million.

Power-One Inc. (Nasdaq: PWER), a Camarillo, Calif.–based provider of power conversion and power management solutions, has raised $60 million in PIPE financing from Silver Lake Sumeru. The deal includes $23.6 million in convertible preferred stock, $36.4 million in senior convertible notes due 2019 and 8.7 million warrants for Power-One common stock.

Quantum Energy Partners is sponsoring the development of hydrocarbon-based energy resources on the Fort Peck Indian Reservation in Montana. No financial terms were disclosed for the commitment, which is being made via a platform called Native American Resource Partners. Quantum’s partners on the effort are the Reservation’s Assiniboine and Sioux Tribes.

RoundTable Healthcare Partners, has acquired NGInstruments Inc., a maker of surgical cutting tools like drills, taps and reamers. No financial terms were disclosed. NGInstruments is the fourth Avalign acquisition, following Nemcomed, Instrumed International and Advantis Medical.

Safilo, a listed Italian eyewear maker, said that four private equity firms are considering an investment. They reportedly are: Apax Partners, Bain Capital, CVC Capital Partners and PAI Partners.

Sarnova, a distributor of health care products in the emergency medical services (EMS) and respiratory markets, has acquired Blue Ridge Medical Inc., a supplier of pharmaceuticals to the EMS community. No financial terms were disclosed. Sarnova is a portfolio company of Water Street Healthcare Partners.

Shinsei Bank (T: 8303) and Aozora Bank (T: 8304) have entered into merger talks. J.C. Flowers & Co. holds around a one-third stake in Shinsei, while Aozora is majority-owned by Cerberus Capital Management.

Starwood Hotels & Resorts has received a preliminary injunction from a U.S. district judge, preventing Hilton Hotels from continuing to develop a new luxury brand called Denizen Hotels. At issue is a pair of ex-Starwood employees who Hilton hired to launch Denizen, and who Starwood claims stole trade secrets. Hilton is a portfolio company of The Blackstone Group.

The Sterling Group, a Houston-based private equity firm, has acquired Velcon Filters LLC, a Colorado Springs, Colo.-based filtration system manufacturer. No pricing terms were disclosed for the deal, which included leveraged financing from BNP Paribas and Amegy Bank of Texas.

StrataCare Inc., an Irvine, Calif.-based provider of national bill review software, workflow and outsource solutions to the workers’ compensation payer market, has sold an undisclosed equity stake to an investor group that includes SV Life Sciences Advisers, Beecken Petty O’Keefe & Co. and Paul Glover. No financial terms were disclosed.

Terra Firma Capital Partners is planning to make a bid for London’s Gatwick Airport, according to Spanish newspaper El Pais. The company is being sold by BAA, which is owned by Spain’s Ferrovial.

Tollgrade Communications Inc. (Nasdaq: TLGD) has agreed to sell the assets of its cable status monitoring product line to an investor group that includes The Hawthorne Group and Rosetta Capital. The deal is valued at $3.15 million, including $2.75 million in cash and $0.4 million in a seller-held note payable over two years.

Westwood One (OTC BB: WWON) has completed a previously-announced restructuring plan that included private equity firm Gores Group increasing its stake in the radio broadcaster to 72.5 percent. Gores originally invested $100 million via a PIPE last year, and has now provided another $25 million in equity (raising its stake to 74.8 percent). Westwood One also refinanced its outstanding long-term indebtedness.

Zotye Auto, a Chinese SUB maker, is in talks to sell between 20 percent and 30 percent of itself to an investor consortium led by SND Ventures Group, a Chinese private equity firm backed by the Suzhou government. The deal is expected to be worth approximately $106 million.