First, you can avoid the system fonts embedding into PDF by setting the config option "Embed System Fonts" to "No".Yet in this case you must be sure that all necessary fonts are installed on the computers where PDFs are shown. The second possibility is to set the config option "Make subsets" to "Yes". In this case ony those symbols that were used in PDF will be embedded I defined the font as a bold font, however the font is not bold in the result PDF.