Abstract:
Bacterial cellulose (BC) has potential applications across various industries with a market
projection of USD 1.5 billion by 2031 (Cruz et al., 2024). The large-scale production of BC
using synthetic media, such as Hestrin-Schramm (HS) medium, is not economically and
environmentally sustainable due to its high cost, dependence on food-grade ingredients, and
limited nutrient diversity. This study assessed the potential of using alternative growth media
and the pH optimum for BC production and its pH dependency. Seven bacterial isolates from
environmental samples were screened for BC production. The isolates from tomato, overripe
pineapple, compost, and legume root nodules, yielded 0.685 g/L, 1.088 g/L, 1.185 g/L, and
0.979 g/L of BC, respectively in HS medium. Three strains, namely, Escherichia coli,
Enterobacter aerogenes, and an unidentified strain isolated from curd did not produce
detectable levels of BC in the same medium. Different media formulations, i.e., fresh pumpkin
juice, king coconut water, synthetic wastewater supplemented with pumpkin extract or
cucumber extract and a modified HS medium made by substituting its 5.0 g/L peptone with
different fresh cucumber quantities, i.e., 100, 200 and 300 g/L were tested as alternative culture
media. The BC production in these media was tested using the four BC producing bacterial
isolates. The data obtained were compared by statistical analysis. The king coconut water
supported low levels of BC production (0.39 g/L by the isolate form tomato and 0.30 g/L by
isolate form overripe pineapple). The HS medium supplemented with 100 g/L fresh cucumber
yielded BC equivalent to the control (standard HS medium), while HS medium supplemented
with 300 g/L fresh cucumber yielded the highest BC (3.323 g/L by the isolate form tomato and
2.549 g/L by the isolate form overripe pineapple which were more than double the amount in
the controls (1.467 and 1.098 g/L respectively). Similarly, the BC yield at pH 6.0 was
significantly higher than that at pH 6.5, and it was more than double in the HS medium
supplemented with 200 g/L fresh cucumber. The other three media did not yield detectable
levels of BC. FTIR spectroscopy confirmed the structural integrity of BC produced. Those
findings indicated the possibility of using low- cost alternative media for BC production. The
results showed that the BC yield could be increased by increasing the substitute concentration
and changing the cultural conditions such as pH level. It also showed the possibility of isolating
high potential BC producing strains from environmental sources.
