Dear  Panagiotis,

You may try to contact the following profesors at School of Envionment Science and Engineering at Tsinghua Univerity, Beijing, P.R. China,

Wu Jing, Associate Professor,

Zuo Jian e, Professor

hello 

Dear Panagiotis G. Kougias

see the following reference. It is good guide to know about  granulation.

WASTE MANAGEMENT SERIES 6

BIOGRANULATION TECHNOLOGIES FOR WASTEWATER TREATMENT

Joo-Hwa Tay, PhD, PE

Stephen Tiong-Lee Tay,† PhD

Yu Liu, PhD

Kuan-Yeow Show, PhD

Volodymyr Ivanov, PhD

School of Civil and Environmental Engineering,

Nanyang Technological University, Singapore

Copyright © 2006 Elsevier Ltd. All rights reserved

Dear Doctor

Actually you can use mesophilic granules as seeding matter, acclimatization is a unique solution for your case.

you can increase temperature  step by step  2 degree per week to avoid shock due to temperature

Dear  Panagiotis,

You may try to contact the following profesors at School of Envionment Science and Engineering at Tsinghua Univerity, Beijing, P.R. China,

Wu Jing, Associate Professor,

Zuo Jian e, Professor

Maybe you can develop your own anaerobic thermophilic granules which contains indigenous microbes where you can optimize the condition base on your needs and location. 

For the amount you need difilcimente find . You could make the adaptation of granular anaerobic sludge mesophilic to thermophilic . in a short space of time that is possible to be achieved.

You can use the mesophilic sludge as seed sludge, and then acclimated by gradually increasing the temperature to thermophilic conditions required

Simple adaptation of mesophilic granules will work. Just give it some time.