You can replace following code:
<?php
echo "<div class='grid3 first'>";
echo "<h1 class='post-title portfolio-single-post-title'>".get_the_title()."</h1>";
echo '<span class="portfolio-categories minor-meta">';
echo get_the_term_list( get_the_ID(), 'portfolio_entries', '<strong>'.__('Categories','avia_framework').': </strong><span>', '</span><span class="text-sep">/</span><span>','</span>');
echo "<span class='date-container minor-meta'>".get_the_time('d M Y')."</span>";
echo '</span>';
echo "</div>";
echo "<div class='grid9'>";
//display the actual post content
the_content(__('Read more →','avia_framework'));
echo "</div>";
?>
with:
<?php
echo "<h1 class='post-title portfolio-single-post-title'>".get_the_title()."</h1>";
//display the actual post content
the_content(__('Read more →','avia_framework'));
?>
however this will also remove the post meta data, etc.