Extraction of Chitosan from Oyster Mushroom (Pleurotus ostreatus) along with Its Physicochemical Characterization and Antibacterial Activity / Ekstraksi Kitosan dari Jamur Tiram (Pleurotus ostreatus) serta Karakterisasi Fisikokimia dan Uji Aktivitas Antibakterinya

Background: Chitosan is a biopolymer derived from the deacetylation of chitin, which is generally obtained from crustacean waste. However, the utilization of more environmentally friendly alternative sources such as oyster mushrooms (Pleurotus ostreatus) has recently been developed. Chitosan exhibits biocompatible, biodegradable properties and antibacterial activity, making it potentially applicable in the food and pharmaceutical industries. Objective: This study aims to extract and characterize chitosan from oyster mushrooms and to evaluate its antibacterial activity against Escherichia coli. Methods: The study was conducted through extraction stages including deproteinization, depigmentation, demineralization, and deacetylation. Chitosan characterization included functional group analysis using FTIR, as well as physicochemical parameter testing such as yield, moisture content, ash content, and solubility. Antibacterial activity was tested using the disc diffusion method at various chitosan concentrations (0.3%, 0.5%, 0.7%, and 0.9%). Results: The obtained chitosan had a degree of deacetylation of 80.64%, indicating successful conversion of chitin into chitosan. The physicochemical characteristics met quality standards, with a yield of 52.84%, moisture content of 0.666%, and ash content of 0.416%. Chitosan was soluble in 2% acetic acid. Antibacterial testing demonstrated inhibitory activity against Escherichia coli, with inhibition zones ranging from 10.1 to 14.2 mm, categorized as strong. Conclusion: Chitosan extracted from oyster mushrooms exhibits good physicochemical characteristics and promising antibacterial activity, indicating its potential as an environmentally friendly alternative material for applications in the food and pharmaceutical fields.

Latar Belakang: Kitosan merupakan biopolimer hasil deasetilasi kitin yang umumnya diperoleh dari limbah krustasea. Namun, pemanfaatan sumber alternatif yang lebih ramah lingkungan seperti jamur tiram (Pleurotus ostreatus) mulai dikembangkan. Kitosan memiliki sifat biokompatibel, biodegradable, serta aktivitas antibakteri yang berpotensi diaplikasikan dalam bidang pangan dan farmasi. Tujuan: Penelitian ini bertujuan untuk mengekstraksi dan mengkarakterisasi kitosan dari jamur tiram serta mengevaluasi aktivitas antibakterinya terhadap bakteri Escherichia coli. Metode: Penelitian dilakukan melalui tahapan ekstraksi meliputi deproteinasi, depigmentasi, demineralisasi, dan deasetilasi. Karakterisasi kitosan meliputi analisis gugus fungsi menggunakan FTIR, serta pengujian parameter fisikokimia seperti rendemen, kadar air, kadar abu, dan kelarutan. Uji aktivitas antibakteri dilakukan menggunakan metode difusi cakram pada variasi konsentrasi kitosan (0,3%; 0,5%; 0,7%; dan 0,9%). Hasil: Kitosan yang dihasilkan memiliki derajat deasetilasi sebesar 80,64% yang menunjukkan keberhasilan konversi kitin menjadi kitosan. Karakteristik fisikokimia memenuhi standar mutu, dengan rendemen sebesar 52,84%, kadar air 0,666%, dan kadar abu 0,416%. Kitosan larut dalam asam asetat 2%. Uji antibakteri menunjukkan adanya aktivitas penghambatan terhadap Escherichia coli dengan zona hambat berkisar antara 10,1–14,2 mm yang termasuk kategori kuat. Kesimpulan: Kitosan hasil ekstraksi dari jamur tiram memiliki karakteristik fisikokimia yang baik serta aktivitas antibakteri yang potensial, sehingga dapat dikembangkan sebagai bahan alternatif ramah lingkungan untuk aplikasi di bidang pangan dan farmasi.