XML serialization and de- serialization C#

public static T DeSerialize(string str)
{
XmlSerializer serializer = new XmlSerializer(typeof(T));
StringBuilder strXml = new StringBuilder();
object obj = null;
using (TextReader reader = new StringReader(str))
{
obj = serializer.Deserialize(reader);
}
return (T)obj;
}

public static string Serialize(object obj)
{
XmlSerializer serializer = new XmlSerializer(obj.GetType());
StringBuilder strXml = new StringBuilder();
using (TextWriter writer = new StringWriter(strXml))
{
serializer.Serialize(writer, obj);
}
return strXml.ToString();
}