TITLE:
Study of Initial Adhesion of a Bacterium to Different Support Materials before and after Conditioning Film of Olive Oil-Mill Wastewater
AUTHORS:
Taoufik Hakim, Souad Lekchiri, Hassan Latrache, Mohamed El Amine Afilal, Abdeslam Jaafari, Safae Tankiouine, Mostafa Ellouali, Hafida Zahir
KEYWORDS:
Conditioning Film, Initial Adhesion, Olive Oil-Mill Wastewater, Physicochemical Properties
JOURNAL NAME:
Advances in Bioscience and Biotechnology,
Vol.11 No.8,
August
10,
2020
ABSTRACT: To improve the start-up speed and efficiency of
bioreactors, biofilm technology is sometimes used. This technology uses various
types of materials to facilitate the adhesion of microorganisms. In this study,
the surface characteristics of inert
substrates and substrates after olive oil-mill wastewater (OMWW) conditioning film were evaluated to understand the impact of OMWW on adhesion
as well as the most suitable material to optimize bacterial adhesion. Three common
substrates made of different polymers were tested for bacterial adhesion before
and after treatment with OMWW: PP (polypropylene), PET (Polyethylene
terephthalate), and PVC (polyvinyl chloride). The surfaces’
physicochemical characteristics were studied by measuring the contact angle
for the studied bacteria strain and the supports, before and after treatment
with OMWW. Results of initial adhesion tests for untreated and treated supports
showed differences in how bacterial cells adhered to substrates. Before treatment
with OMWW, PVC and then PP showed a significant adhesion capacity, double that
of PET [PVC: 1.58 × 105 CFU/cm2, PP: 1.48 × 105 CFU/cm2 and PET: 0.72 × 105 CFU/cm2]. After treatment with OMWW, initial
bacterial adhesion increased by 106 (from 105 CFU/cm2 for untreated supports to 1011 CFU/cm2 for treated
supports), and PET followed by PP demonstrated the highest adhesion capacity, 2
and 1.7 times more than PVC, respectively [PET: 1.39 × 1011 CFU/cm2, PP: 1.15 × 1011 CFU/cm2 and PVC: 0.67 × 1011 CFU/cm2]. OMWW conditioning film affects the physicochemical
characteristics of plastic supports, especially the donor electron character,
and improves the initial adhesion of bacteria to substrates (105 to
1011 CFU/cm2). Therefore, surfaces’ physicochemical
characteristics were important in the initial adhesion of the bacteria onto the
support before and after treatment.