This is a really interesting and significant topic, and if we are able to harness these processes you went over correctly, it could mean really big things for fighting climate change. Your presentation really showed the hard work you put in and I learned more about these microorganisms (especially the anoxygenic purple bacteria), so thank you! 

Because not everyone has done the research that you did, I would suggest giving more well known examples or names of microorganisms early on. For example, diatoms are a type of algae and more people have heard of that term. This way, your audience has a better idea of what you're teaching them. 

Using biomass for energy is a way to avert some fossil fuels being burned, and that could slow climate change. However, there's still some CO2 emissions being given off by biomass burning, so we need to keep making scientific advancements in that area to make it even more environmentally safe. 

The part about your presentation that I really liked was talking about how the microorganisms can actually take CO2 out of the atmosphere, and that's also called carbon capture. They can also be used to make our water cleaner. We actually have a really cool wastewater treatment plant in the Chicagoland area that uses algae and I think you can request tours of the facility to see them using microorganisms to help treat the water. If your parents or teachers are looking for ideas for field trips, then that's a good one. https://mwrd.org/mwrds-resource-recovery-work-featured-global-documentary 

Or you can watch this video to get an idea of what they do https://vimeo.com/76662009 (microorganism talk starts at 4:25)