Isolation, Screening, and Identification of Local Bacterial Isolates Producing Bio-Cellulose

The current study aims to easily, quickly, and cheaply select the local bacterial isolate that produces bacterial cellulose. Ten samples of spoiled fruits (triplicate for each) were taken in Al-Kut City/ Wasit Province/ Iraq. A modified H-S medium was used to isolate the local bacteria from spoiled fruit samples. One-hundred and twelve bacterial isolates were obtained from all samples, where the lemon sample give the highest number of isolates, as it reached ۲۰ isolates, while the banana sample gives the lowest number of isolates reached to ۶ isolates. The two steps of screening were achieved to select the best cellulose-producing local isolate, results from the primary screening indicated that only ۱۸ isolates appeared a clear ability to create clear zones as an indicator to produce bacterial cellulose, and the isolates TELE۸, TELE۱۱, TEKI۴, and TEAP۵ gave the highest clear zones of ​​۷.۵, ۶.۱, ۶.۲, and ۶.۵ cm, respectively. Also, the second screening step confirmed the results collected from the first step, as the results hydrogel test indicated that only ۱۸ strains showed the ability to produce bacterial cellulose, while the other isolates were unable to do so, as the results showed that the isolate TELE۸ was superior in its ability to produce bacterial cellulose than isolates TEK۱۱, TEKI۴, and TEAP۵. Therefore, the local isolate TELE۸ was chosen as the best isolate that produces bacterial cellulose. Thereafter, the phenotype and genotype characteristics were used to identify the TELE۸ isolate; its results indicated that the isolate belongs to Komagataeibacter xylinum (previously named first Acetobacter xylinum, and then Gluconacetobacter xylinus). The three methods (static, shaker, and fermenter) were used to produce the bacterial cellulose by using the best local bacterial isolate Acetobacter xylinum TELE۸ in HS medium. The results revealed that the highest production of BC (۲۲.۸ g/۲۰۰ ml medium) was obtained when using the fermenter method, while the shaker method did not give the productivity of bacterial cellulose.

Keywords:

Acetobacter xylinum , Bacterial Cellulose , spoiled fruit , HS medium , Fermenter