Chitin is a biopolymer used in various industries, including biomedical, pharmaceutical, medical, and food. Today, the vast majority of chitin is obtained from waste shellfish. Shellfish chitin has an inherent impurity problem because chitin in these organisms is embedded in other organics and inorganics. Thus, new sources have been investigated. Diatoms, particularly Thalassiosira and Cyclotella species, have the potential to be the providers for applications requiring high quality through their unique ability to biosynthesize and extrude chitin nanofibers. The primary aim of this study is to study this potential. This investigation entailed the cultivation of three Thalassiosira strains according to a standard cultivation protocol under photobioreactor conditions. The secondary aim was to assess the possibility of commercially valuable co-product generation. For this, biomass protein, lipid, and fatty acids contents were analyzed. Chitin productivity varied significantly between the strains. The peak productivities and final concentrations ranged from 4 to 25 mg/L-day and from 60 to 250 mg/L, respectively. Average fiber diameters ranged from 68.5 to 95.0 nm. Silicon limited growth increased the chitin biosynthesis in T.weissflogii 1336 and T.pseudonana 2135. Biomass lipid contents of over 45% were obtained with T.pseudonana 2135 under silicon depletion. The fatty acid profiles indicated the suitability for application as live aquaculture feed for T.weissflogii 1336, and biodiesel feedstock material for T.pseudonana 2135. The highest biomass protein contents were about 30%, which were obtained under silicon availability. This study, for the first time, assessed the chitin productivity of Thalassiosira strains and demonstrated unique multiproduct generation scenarios.