Dr. D'Souza is an accomplished microbiologist, and an Associate Professor at the Dept. of Microbiology, Goa University. His research on photosynthetic bacteria has demonstrated that this bacterial biomass can be successfully used to treat sewage, grow fish in sewage, as well as control pollution in water by converting waste into resource. His study of the detrimental effects of chemical affluent from aquaculture ponds on traditional fisheries, has resulted in the implementation of stricter guidelines for the maintenance and spread of aquaculture ponds in the country. In 1998, his letter to the High Court seeking to restrain the government's initiative to convert the historical Reis Magos Fort into a 5-star hotel, was admitted as a writ-petition and allowed to stand.

In addition to his extensive research on the role of marine-fungi in the deterioration of wood and cellulosic materials, Dr. D'Souza has pioneered the enzymatic methodology to detect pollution in estuaries from residential, commercial and industrial sources. Through the use of specific enzymes, environmental agencies are now able to effectively respond with corrective and punitive measures within hours of the occurrence of such pollution. Dr. D'Souza has further demonstrated that micro-organisms can also be used to convert garbage into biofertilizers, as well as convert solid from mining wastes into a fertile zone suitable for cultivation. Dr. D'Souza has presented his research papers at national and international conventions and symposiums, and his research studies have appeared in scientific journals in India and abroad.