Microalgae-based biorefinery coupled with effluent treatment (MBBET) is an approach that makes biomass production economically advantageous. It can produce value-added products from a circular bioeconomy perspective for a variety of industries. Although the global microalgae market is growing at a rapid rate of 7.39% per year and 70–90% of world's technological information is consolidated in patents, this source of technical data is still underexamined in the microalgae field. Technological prospecting is a powerful tool that provides insight into expanding knowledge and innovation in companies, providing inputs for competitive intelligence, improving decision-making, and forecasting technological changes. Thus, this review aims to fill this research gap by presenting a bibliometric analysis of patents conjugated with a natural language processing (NLP) textmining approach to transforming raw big data into useful information. The state-of-the-art prospective patents on MBBET are disclosed, demonstrating the potential of this integration, its historic-technological trends, the different effluents treated, and bioproducts of market interest. The research was conducted using the Espacenet and Orbit® databases. The data were recovered from patent documents from the last 20 years using a combination of the keyword “Microalgae” and code C02F3 (Biochemical effluent treatment), where 422 documents were recovered from Espacenet and 664 from Orbit®. In this paper, we show that patents are a noteworthy source of information for the advancement of microalgal biorefinery areas, especially when they are compared to scientific articles. Although biotechnological potential of algal biomass is still underexploited, technological gaps and active technologies are highlighted. MBBET is a promising key to mitigate global environmental challenges and is an expression of the new paradigm of water-food-energy. Future challenges are proposed to sketch perspectives on new avenues for technological improvements.