SQLite c# : How to save and retrieve custom object in sqlite BLOB datatype?

There is a custom object(ex company) and list of custom object (ex employee) which needs to be saved in a BLOB datatype, Below is the piece of code I have tried without success. I have tried DbType.Binary but it did not workout.

Below is the piece of insert query :

sql_cmd.Parameters.Add("@company", DbType.Byte); 
sql_cmd.Parameters["@company"].Value = (Company)root.company;


sql_cmd.Parameters.Add("@employees", DbType.Byte);
sql_cmd.Parameters["@employees"].Value = ((List< Employee >))root.employeeList;

Exception :

System.FormatException was unhandled by user code.
Message=Input string was not in a correct format.

Below is the associated classes

 class Company
    {
        public string id { get; set; }
        public string name { get; set; }
        public List<Package> packages { get; set; }
        public string description { get; set; }
    }

 class Employee
    {
        public string id { get; set; }
        public string name { get; set; }
        public object description { get; set; }
        public Address address { get; set; }
        public Contact contact { get; set; }
        public string enterpriseId { get; set; }
        public object createdDate { get; set; }
        public object modifiedDate { get; set; }
}