All interest and principal repaid by the loan recipients shall be paid to the State Treasurer for deposit in the fund. Said moneys shall be deposited in the first instance (by the State Treasurer) in one or more banks or trust companies, in one or more special accounts, and each of such special accounts shall be continuously secured by a pledge or direct obligations of the United States of America or of the Commonwealth, having an aggregate market value, exclusive of accrued interest, at all times at least equal to the balance on deposit in such accounts. Such securities shall either be deposited with the department or be held by a trustee or agent satisfactory to the department. All banks and trust companies are authorized to give such security for such deposits. The moneys in said account shall be paid out on the warrant or other order of the secretary of the department, or of such other person or persons as the department may authorize to execute such warrants or orders.