The immobilized bead was prepared with polyvinyl alcohol
(PVA) and sodium alginate. Firstly, a colloidal solution was obtained
by dissolving the 9% PVA and 0.9% sodium alginate (w/v) in deionized
water in a sterilizer at 120 ◦C. Secondly, the colloidal solution
cooled to about 25 ◦C of room temperature was mixed uniformly
either with the Mycobacterium sp. CHXY119 cell suspension of
OD600 1.0 at a rate of 10% (v/v) to prepare the sole Mycobacterium
sp. CHXY119 immobilized bead or with both Mycobacterium sp.
CHXY119 and Pseudomonas sp. YATO411 cell suspensions at a rate
of 5% to prepare the Mycobacterium sp. CHXY119 and Pseudomonas
sp. YATO411 immobilized bead. Thirdly, the cell-contained colloidal
solution was slowly injected through a tip driven by a
peristaltic pump into a curing solution containing 2.5% CaCl2 and 5%
H3BO3 in w/v. The white cell-immobilized bead then formed after
1–2 h of immersion. Finally, the formed cell-immobilized bead was
washed three times with sterile water, followed by immersion of
6 h in 5% (w/v) KH2PO4 to promote the mechanical strength.