* H1 profit 1.34 bln dhs vs 1.09 bln dhs yr-ago
* Joint venture income 2.12 bln dhs vs 1 bln dhs
* Total income 1.32 bln dhs vs 2.11 bln dhs (Adds detail, context)
ABU DHABI/DUBAI, Sept 18 (Reuters) - Mubadala, the Abu Dhabi state-owned investment fund with a mandate to develop the emirate's economy, posted a 23 percent increase in first-half profit, aided by higher income from joint ventures and one-off gains.
One of Abu Dhabi's few state-controlled vehicles to publish results, Mubadala has interests in semiconductors, energy, aerospace and real estate among others, including General Electric, private equity firm Carlyle and local companies such as Aldar Properties and Tabreed .
Income from Mubadala's joint venture businesses doubled to 2.12 billion dirhams, thanks largely to Emirates Global Aluminium - one of the world's largest aluminium producers - and Dolphin Energy, which pipes gas to the United Arab Emirates from fellow Gulf state Qatar.
That helped to lift net profit to 1.34 billion dirhams ($364.8 million) in the first six months of 2014 from 1.09 billion dirhams in the same period last year, its financial statement said.
Mubadala's profit was also boosted by a near-tripling of income from one-off equity-related gains and disposal of subsidiaries, to 1.44 billion dirhams.
The company sold a district cooling plant in Abu Dhabi's Al Maryah island and aerospace business Abu Dhabi Aircraft Technologies (ADAT) to Etihad Airways.
However, total comprehensive income fell by 37.4 percent year on year to 1.32 billion dirhams, with returns from its financial investment portfolio dropping to 388 million dirhams from 1.3 billion dirhams. (1 US dollar = 3.6729 United Arab Emirates dirham) (Reporting by Stanley Carvalho and David French; Editing by Mark Potter and David Goodman)