Insert terms to term store using SharePoint object model

SPSecurity.RunWithElevatedPrivileges(delegate()

                {

                    using (SPSite oSite = new SPSite(siteUrl))

                    {

                        using (SPWeb oWeb = oSite.OpenWeb())

                        {

                            oWeb.AllowUnsafeUpdates = true;

                            TaxonomySession _TaxonomySession = newTaxonomySession(oSite);

                            //Get instance of the Term Store

                            TermStore _TermStore = _TaxonomySession.TermStores[Constants.ManagedMetaDataServiceAppName];

                            //Get instance of Group

                            Group group = _TermStore.Groups.FirstOrDefault(e => e.Name == Constants.AIPTermsGroup);

                            //Get the termset of projectType

                            TermSet termset_ProjectTerms = group.TermSets.FirstOrDefault(e => e.Name ==Constants.ProjectTermsTermSet);

                            #region BU

                            //Get the term --BU

                            Term term_BU = termset_ProjectTerms.Terms.FirstOrDefault(e => e.Name ==Constants.TermBU);

                            //Check for BU not emptty

                            if (!string.IsNullOrEmpty(BUTerm))

                            {

                                //Check whether the current projects BU exists in BU term

                                if (term_BU.Terms.Where(t => t.Name == BUTerm).Count() == 0)

                                {

                                    //Add the term if it doesnt exists

                                    term_BU.CreateTerm(BUTerm, lcid);

                                }

                            }

                            #endregion BU

                            //commit the changes to SharePoint

                            _TermStore.CommitAll();

                            oWeb.AllowUnsafeUpdates = false;

                        }

                    }

                });