Volume 18 2026 PRELIMINARY STUDY: SCREENING OF PROTEASE-PRODUCING ENDOPHYTIC BACTERIA TO BE DEVELOPED FOR NANO-FORMULATED BIOFERTILIZER FOR COCOA PLANT GROWTH. Authors Ishak Zubir 1, Ernie Eileen Rizlan Ross 2*, Rahman, M.Z.A.3, Lea Johnsiul 3, Norasekin Tamchek 3, Roslina, M.S. 3, Nurfadzilah, M.4 and Mohd Anuar, S. 1 ABSTRACT The production of extracellular protease enzymes by cocoa endophytic bacteria was evaluated using the skim milk agar hydrolysis assay. The formation of clear hydrolysis zones indicated the secretion of proteases capable of degrading casein, the major protein component in skim milk. Among the five bacterial isolates tested, four isolates (PA, PD, BK, and UL) exhibited proteolytic activity, while isolate BL showed no detectable hydrolysis zone under the experimental conditions. Isolate PA demonstrated the highest protease activity with an average hydrolysis zone of 11.1 mm, followed by BK (9.2 mm), PD (9.0 mm), and UL (6.7 mm). The variation in hydrolytic activity among isolates indicates that extracellular protease production is strain dependent and influenced by bacterial metabolic capacity and environmental conditions. The high proteolytic activity exhibited by isolate PA suggests its potential for improving nutrient mineralization and supporting plant growth-promoting functions. The findings indicate that isolate PA is a promising endophytic bacterial candidate for further physiological, molecular, and greenhouse studies toward the development of sustainable microbial biofertilizer formulations for cocoa cultivation. VIEW PDF DOWNLOAD