Thank you JakePT. Finally solved.
/**
* Example: [wp custom_taxonomy="taxonomy_slug"]
*/
function list_terms_custom_taxonomy( $atts) {
extract( shortcode_atts( array(
'custom_taxonomy' => '',
), $atts ) );
ob_start();
global $post;
$string1 .= get_the_term_list( $post->ID , $custom_taxonomy, ' ' , ', ' , ' ' );
$string1 .= ob_get_clean();
return $string1;
}
add_shortcode( 'ct_terms', 'list_terms_custom_taxonomy' );
add_filter('widget_text', 'do_shortcode');
// shortcode to use [ct_terms custom_taxonomy=customtaxonomyname]