* New president has moved against predecessor's allies
* Taking helm of ruling party will cement his power
* Move coincides with sacking of wealth fund asset manager (Recasts, pvs JOHANNESBURG)
By Herculano Coroado
LUANDA, April 27 (Reuters) - The most powerful body in Angola's ruling MPLA party said on Friday it had approved the candidacy of state president Joao Lourenco to become head of the party, replacing his predecessor as head of state Jose Eduardo dos Santos.
The move coincided with an announcement by Angola's $5 billion sovereign wealth fund that it was sacking Swiss-based Quantum Global as its asset manager because it was concerned about the way its capital was being invested.
Both developments will further cement the political grip of Lourenco, who has taken action against dos Santos' allies and removed family members from key positions while pledging to root out endemic corruption and clean up public finances in Africa's No. 2 crude producer.
Dos Santos' son Jose was formerly head of the fund but has since been removed by Lourenço, who has also overseen the sacking of his daughter Isabel as head of state oil company Sonangol.
Lourenco took over as state president in September last year when dos Santos stepped down after almost four decades in power, but the latter remained head of the MPLA, which has ruled Angola since it won independence from Portugal in 1975.
The MPLA's politburo, the highest-ranking organ in the former Marxist party that was aligned to Moscow during the Cold War, said in a statement that it had "approved the candidacy of Comrade João Lourenço, currently Vice-President, to the position of MPLA President."
The next MPLA president will be formally appointed at a party congress in September.
Dos Santos' position as head of the party was widely regarded as an attempt to maintain control of the state but Lourenço has shown he is in charge.
The action against Quantum Global follows this pattern as the new administration seeks to weed out the influence of dos Sanstos' appointees in a bid to woo investors and key lenders.
Angola's sovereign wealth fund FSDEA said in a statement that it had "great concerns about Quantum Global’s approach to investment of the FSDEA funds."
"As a consequence of investigations through leading international global consultants and advisers, FSDEA is taking steps to remove Quantum as its asset manager," it added.
Quantum Global said all Angola's money under its management was accounted for and that the dispute was a contractual issue. QG was appointed in 2012, with most investments made in 2015.
Friday's announcement comes just weeks after Mauritius froze bank accounts and suspended business licences linked to QG Investments Africa Management following a visit by Angolan officials.
QG Investments Africa Management, which said it was cooperating with authorities in Mauritius, is run by Jean-Claude Bastos de Morais, QG founder and group chairman and a business partner of dos Santos' son.
Quantum Global has demanded that Mauritius authorities explain their decision to suspend its business licenses on the Indian Ocean island nation. (Additional reporting by Michael Shields in Zurich Writing by Ed Stoddard Editing by Hugh Lawson and Richard Balmforth)