Vanillin is one of the most commonly utilized aromatic flavoring chemicals in the food and cosmetics industries. It is derived from natural sources, making it more expensive than synthetic vanillin, and it constitutes less than one percent of the annual market demand.Pineapple peel stands out as a valuable source for extracting ferulic acid, which in turn is utilized in the synthesis of vanillin. As a result, researchers are exploring alternative methods for producing vanillin, such as biotechnological production from ferulic acid. In this study, the capability of pineapple peels as a substrate for the microbial fermentation of ferulic acid by Aspergillus nigerto produce vanillin in a single step was investigated. The biotransformation of ferulic acid from pineapple peel by alkaline hydrolysis was optimized using different concentrations of NaOH. Further, the detection and quantification of vanillin and ferulic acid were carried out using High-Performance Liquid Chromatography and thiobarbituric acid (TBA) method. Through HPLC analysis, the amount of vanillin concentration produced from the supernatant culture was 1.47±0.24 μg/ml from 1.0 M NaOH concentration and 2.83±0.44 μg/ml from 2.0 M NaOH concentration. From this study, 57.09±1.84 μg/ml and 83.84±4.01 μg/ml of ferulic acid were produced from the 1.0 M NaOH and 2.0M NaOH,respectively. In addition, using the TBA technique, vanillin concentrations were calculated, resulting in 12.92 ± 0.54 μg/ml and 15.38 ± 0.77 μg/ml from 1.0 M and 2.0 M NaOH concentrations, respectively. Briefly, the pineapple peel has been discovered as a good source for vanillin production using Aspergillus nigerin the fermentation method.