HI All, 

I am trying to write simple batch class in which i have send multiple emails from the finish method of batch class , Please see the below code that i am trying to use: 
 

global class NotifyBatch2 implements Database.Batchable<sObject>, Database.Stateful {

datetime dt = System.now()-1;
public string query = 'select Id, name,Status__c,CreatedDate,Materials_Meeting_Date__c,Materials_Due_Date__c,CreatedBy.Email,Submitter__c,Book_Coverage__c,Notes__c,Materials_Request_Organization__c from MR_Product__c where Status__c=\'Pending Submission\'';

//Here i am getting the problem.
public List<Messaging.SingleEmailMessage>  mails = new List<Messaging.SingleEmailMessage>();

global database.querylocator start(Database.BatchableContext BC)
{

    return Database.getQueryLocator(query);
}

global void execute(Database.BatchableContext BC, Sobject[] scope)
{ 


  //
    EmailTemplate emailTemplate = [select Id, Body  from EmailTemplate where DeveloperName = 'BOOK_REQUEST_Template'];

    for (MR_Product__c  item : (List<MR_Product__c>)scope) {
        
    
            Messaging.SingleEmailMessage email = new Messaging.SingleEmailMessage();
             string MatDueDate = string.valueOfGmt(item.Materials_Due_Date__c);
             string MatMeetingDate = string.valueOfGmt(item.Materials_Meeting_Date__c);      
                    
                    string body = emailTemplate.body;
                    
                    body  = body.replace('{!MR_Product__c.Submitter__c}', item.Submitter__c);
                    body  = body.replace('{!MR_Product__c.Materials_Request_Organization__c}', item.Materials_Request_Organization__c);
                    body  = body.replace('{!MR_Product__c.Materials_Due_Date__c}', MatDueDate );
                    body  = body.replace('{!MR_Product__c.Materials_Meeting_Date__c}', MatMeetingDate);
                    
                    if(item.Notes__c!=null && item.Notes__c!=''){
                    body  = body.replace('{!MR_Product__c.Notes__c}', item.Notes__c);
                    }
                     if(item.Book_Coverage__c!=null && item.Book_Coverage__c!=''){
                    body  = body.replace('{!MR_Product__c.Book_Coverage__c}', item.Book_Coverage__c);
                    
                    }

                    email.setToAddresses(new String[] {item.createdby.Email});
                    email.setSaveAsActivity(false);
                    email.setPlainTextBody(body);
                    
                    email.setTemplateId(emailTemplate.Id);
                    system.debug('Checkemails' + email);
					//Here i am getting problem
                    mails.add(email);
            
           Messaging.sendEmail(new Messaging.SingleEmailMessage[] {email});
       
    }
    
          
}

global void finish(Database.BatchableContext BC) {

    // for sending final emails:
    Messaging.sendEmail(mails);



}


}

Error i am getting : 

First error: Not Serializable: com/salesforce/api/fast/List$$lcom/salesforce/api/Messaging/SingleEmailMessage$$r

I have already tried making it as transient with no sucess, 

All i want is to send Emails for all records "created by user " in finish method i single go, plaese help , thanks