Bacterial cellulose (BC) based on sago liquid waste has been developed to be used as food packaging. This study investigated the physicochemical and mechanical properties of modified BC film and its application as food packaging. The modified BC film performed carboxymethyl cellulose (CMC) as a stabilizer and glycerol as a plasticizer. Films were prepared by casting technique using BC as the primary material and composites with various concentrations of CMC and glycerol (0.5%, 1%, and 1.5%, v/v). BC film was applied as the packaging of meat sausage, and the quality of meat sausage was measured based on weight loss, moisture content, pH, protein content, and total microbial count. The addition of CMC and glycerol influences the physical and mechanical properties of BC composites film. The best mechanical properties of edible BC film were collected by adding 1% CMC and 1% glycerol with a tensile strength of 17.47 MPa, elongation at a break of 25.60%, and Young’s modulus of 6.54 GPa. FTIR analysis showed the characteristic bands of BC, and the addition of CMC and glycerol slightly changed the FTIR spectrum of the composites. The utilization of modified BC-based sago liquid waste film as the packaging of meat sausage could maintain sausage quality during 6 days of storage at room temperature. Therefore, edible BC film has the potential to be used as food packaging.

Highlights Bruguiera cylindrica is a mangrove plant in North Sumatra with limited information on its microbial endophytes. An enzyme bioprospection study was conducted revealing Vibrio alginolyticus as a prominent proteolytic strain. Vibrio alginolyticus Jme3-20 produced a multitude of extracellular enzymes such as amylase, cellulase, chitinase, phosphatase, and urease. This is the first report on finding Vibrio alginolyticus from mangrove area of North Sumatra.

Keratinase is a group of protease enzymes which acts to degrade keratin. Keratin is a fiberous protein difficult to be degraded because of hydrogen and disulfide bonds. The purpose of this study was to isolate and to identify keratinase coding genes using molecular approach. The object of this study was crocodile feces from Asam Kumbang crocodile farm. Bacterial isolation was done by using feather agar (FA) and was screened in skim milk agar. Keratinolytic bacteria isolates were identified molecularly with 16S rDNA specific markers. Detection of keratinase gene was done by using keratinase-specific primers through primer3 application (version 0.4.0). The result showed that isolate FB3 are potential to produce keratinase. Isolate FB3 showed a clear zone in FA and SMA. FB3 was 100% similar to Aeromonas hydrophila. Amlification using kerD gene specific primer showed that FB3 was a novel bacteria possessing kerD gene with a fragment length of 750 bp. This result provided a new database of kerD gene.

Ki rinyuh (Chromolaena odorata) is one of invasive plants species in Indonesia with potency as traditional medicine. The purpose of this study was to verify the presence of endophytic bacteria symbionts with Chromolaena odorata, and to evaluate the plant-growth promoting properties of endophytic bacteria in producing IAA, producing hydrolytic enzymes (α-amylase, β-amylase, cellulase, chitinase, protease) solubilizing phosphate. Isolation of endophytic bacteria was carried out by surface sterilizing the samples of roots, stems, leaves with 70% alcohol and 2% sodium hypochlorite, followed by direct plating of organ parts (1-2 cm) on top of Trypticase Soy Agar (TSA) medium. Bacterial isolates were differentiated through morphological biochemical characterization. A total of 19 endophytic bacteria were successfully recovered from Chromolaena odorata roots, stems and leaves. Four isolates produced the highest IAA, namely BECA1 (109 ± 0.98 ppm), BECA5 (104.13 ± 0.32 ppm), BECA8 (104.13 ± 0.71 ppm) and BECB3 (83.29 ± 0.47 ppm). Three isolates exhibit the highest phosphate solubilization (+++) namely BECA5, BECA1, BECA8 after 4 days of incubation. Furthermore, BECB3 produced a considerable hydrolytic enzyme activities: β-amylase (+++), α-amylase (++), cellulase (+++), chitinase (++) and protease (+++) compared to other isolates. Our result may provide an insight upon the beneficial interaction by plant-growth promoting endophytic bacteria to support the invasiveness of the plant.

Keratinase is a proteolytic enzyme capable on degrading the hardy polymeric biomolecule or keratin. In recent days, the utilization of keratinolytic microorganisms is seen as a promising way in recycling the keratin wastes from the avian and mammalians into valuable derived products. Previous study has reported the presence of a keratinolytic bacterium, later identified as Azotobacter chroococcum B4 obtained from dump soils. The present study investigates the enzyme characteristics of keratinase produced by this strain based on the physical appearance of final degraded product using SEM, the molecular weight of keratinase using SDS-PAGE, the effects of nutrition (C/N-source) on strain production of keratinase and the enzyme stability in metal ions solution. The molecular weight of keratinase produced by A. chroococcum B4 was about 30 kDa. Both sucrose and tryptone supplementation increase the keratinase activity by 71.7 and 97.8 U/mL after 96 h of cultivation. Metal ions, Ca 2+ , Mg 2+ , Mn 2+ , Na + , and K + are regarded as activators by increasing the relative activity of keratinase by 117, 166, 111, 113, and 112% respectively, while phenylmethylsulfonyl flouride (PMSF) is regarded as inhibitor by decreasing the relative activity down to 31%. Based on the metal ion characteristics, this strain produced a serine-protease type of keratinase which may further studied for its application in the field.

Hydrolysis of keratin waste by fungi is an alternative biotechnology for recycling and valorization by utilizing its keratinolytic activities. The purpose of this study was to isolate the keratinolytic fungi and to test the degradation ability of chicken feather keratin. Crocodile feces and soil samples were collected from crocodile breeding farm in Asam Kumbang, North Sumatera. Casein and keratin of basal feather agar of 1% was used to isolate keratinolytic fungi. Fungal isolate was grown in feather meal broth incubated at 28°C and shake at 180 rpm using shaking orbital. Remain chicken feather was weighted after application of keratinolytic fungi. After 4 days of incubation two fungi showed to have clear zone around their colony. THB7 was found to have relatively high hydrolysis zone in casein, while FB4 degraded more keratin in keratin agar. Most feather was degraded in 10, 12, and 16 days in THB7, FB4, and THB4 application respectively. THB4 showed to degrade feather to 1.6 g, while FB3 and FB4 remained feather to 2 and 3.4 of 10 g respectively. Further study includes molecular identification, characterization and keratinase production should be done.

The present study was conducted aiming to isolate and characterize endophytic bacterial isolates with antibacterial ability, phosphate solubilization, and proteolytic activity from rhizomes of the Zingiberaceae family (Etlingera sp., Globba patens, Globba pendula, and Zingiber multibracteata). Nineteen bacterial isolates were obtained from Zingiberaceae rhizomes with isolate codes of EZS27, EZS18, EZS19, EZS25, EZS16, EZS08, EZS09, EZS13, EZS20, EZS14, EZS10, EZS11, EZS03, EZS05, EZS06, EZS43, EZS45, EZS47, and EZS28. The screening of the endophytes for antibacterial activity was done through the paper disc method. Four bacterial isolates presented antibacterial activities. EZS06 isolate inhibited the growth of EPEC (11 mm), P. vulgaris ATCC 13315 (10 mm), and L. monocytogenes BTCC B693 (9 mm). Also, EZS20 isolate inhibited the growth of S. aureus ATCC 29213 (17 mm), EZS28 isolate inhibited MRSA ATCC 43300 (8.6 mm), and EZS45 isolate inhibited S.  Epidermidis ATCC 12228 (9 mm). The EZS19, EZS03, and EZS16 isolates dissolved the phosphate most effectively. Eight isolates (EZS19, EZS47, EZS27, EZS25, EZS09, EZS20, EZS45, and EZS06) showed the best protease activity. In general, our results showed that the endophytic bacterial strains can be used as a new and useful antibacterial agent since it showed antibacterial activity and chemical diversity. Furthermore, it also has the potential for exploitation in a wide variety of medical, agricultural, and industrial areas.

The habitat of endophytic bacteria in plant tissues making it automatically used by plants to protect themselves against pathogenic bacteria. Endophytic bacteria have been applied in various fields, including agriculture, pharmacy, medicine, and biotechnology. This review was carried out to summarize recent studies focusing on the diversity of endophytic bacteria derived from traditional medicinal plants which have antibacterial activity and extracellular enzymes. This article was prepared and written by referring to literature studies collected from books and online journal publication. The literature review of endophytic bacteria focused on Vernonia anthelmintic, Saurauia scaberrinae, and Ki rinyuh (Chromolaena odorata) plants. The results revealed that endophytic bacteria obtained from Vernonia anthelmintic plant is from Micrococcus, Bacillus, Pseudomonas, Stenotrophomonas, and Pantoea genus which possess the same biological properties as the host plant, producing antibacterial activity. Saurauia scaberrinae plant successfully isolated endophyte fungus Phoma sp. which produces phomodione (4) and cercosporamide. Phomodione (4) exhibit inhibitory activity against S. aureus, P. ultimum, S. sclerotiorum and R. solani. Cercosporamide exhibits inhibitory activity against S. aureus. Endophytic bacteria were also isolated from Ki rinyuh (Chromolaena odorata), including BECB3, BECB 4, BECA 8, BECA 5, BECA 1, and BECA 10 isolates which have extracellular enzyme activities such as β-amylase, α-amylase, cellulase, chitinase, and protease. Understanding endophytic bacteria in medicinal plants can help researchers apply them effectively.