Fungi can secrete enzymes that break down lignocellulosic biomass such as wood chips and wheat straw. Over 200 strains of fungi were sampled from soil and plant samples across Vietnam by researchers at the Food Industrial Research Institute (FIRI). From these strains, six were selected for further studies due to their ability to grow at surprisingly low pH. During the internship, we focused on two main applications. Firstly, each of these fungi were grown in shake flasks containing 2% tannic acid as the carbon source. For the Penicillium sp1 fungus, one enzyme was isolated using a size-exclusion column. The tannase-specific rhodanine assay was used to conclude that this enzyme is active on tannins, which are a class of plant defense molecules that are often inhibitory to other organisms as they are able to precipitate proteins. The fungal tannase was found to be active on a variety of gallotannin substrates and within a wide pH range between1.75–9.5. Secondly, the fungi were grown on various carbohydrates: the monosaccharides glucose and mannose, and the polysaccharides xylan and cellulose. The proteins secreted from these cultures at various pH values were assessed using gel electrophoresis. For xylan at pH 2.5 and 5.5, we found significant differences for each species between the pH values. These secreted proteins will be identified using proteomics and then produced heterologously for biochemical study. To enable this, we next generated cDNA libraries for each species, via RNA extraction and reverse transcriptase treatment. Primers will be designed using the annotated genomes and used to amplify genes of interest to produce expression strains for protein production in a model microorganism. These acidophilic fungi produce tannases as well as CAZymes at a wide range of pH values. Further studies may include scaling up protein production in a bioreactor in an effort to use these enzymes industrially.