Hi,
From here: https://www.microsoft.com/biztalk/en/us/system-requirements.aspx#Software_Prereq
SQL Server 2005 SP2 or 2008 Microsoft SQL Server is a relational database server capable of efficiently processing high volumes of data. For optimal performance, we recommend that you use Enterprise Edition of SQL Server 2008. Note:In order to fully use the BizTalk Server 2009 SDK, or deploy BizTalk Server applications from a Visual Studio development environment, you must also install the SQL Server Development Tools. Note:Using SQL Server Express Edition in a production environment is not recommended. The Express edition does not include certain features needed by BizTalk Server.