The feasibility of nutrient uptake by Chlorella vulgaris using a cheap carbon source such as plantain peel extract was studied and its biomass utilized for bioethanol production. Unripe plantain peels were obtained, processed, infused for 48 hrs, extracted and cultivated with the Chlorella species for a period of fourteen days. The microalgal carbohydrate content was hydrolyzed with acid and enzyme while the hydrolysate fermented with 10% concentration of Saccharomyces sp. and Aspergillus sp. at 30˚C and pH 4.5 using Separate Hydrolysis and Fermentation (SHF) and Separate Hydrolysis and Co-culture Fermentation (SHCF) methods. Results show that maximum cell growth of 1.56 (OD) and biomass concentration of 19 g/l were obtained with 48 hrs infusion. The result indicated that C. vulgaris utilized PPE medium as a sole carbon substrate and stimulated the secretion of biomass. The highest reducing sugar of 0.63 mg/ml was obtained after hydrolysis of the biomass, while the ethanol production yield of 0.33 g/l was obtained after fermentation. The ethanol production yield increased with the increase in fermentation time, while the reducing sugar was reduced after five days of fermentation. The highest ethanol percentage of 10.82% v/v was obtained from the distillate.This study showed that plantain peel can be utilized by C. vulgaris which provides a feasible route of reducing production cost of bioethanol from a cheap carbon substrate for biomass and bioenergy production.

Microbial exopolysaccharide (EPS) emerged as a fast and high yielding sustainable polymeric substance which can be used as an alternative to synthetic polymer in industry. In this study, the influence of various nutritional and environmental factors of fermentation medium on bacterial growth and EPS production was evaluated by one factor at a time optimization. Efficient production medium was chosen from four different basal media and its carbon and nitrogen substrates were varied among organic and inorganic sources. Feasibility of bacterial utilization of some agricultural wastes as carbon and nitrogen sources to synthesize exopolysaccharide was compared. Carbon source of the fermentation medium was replaced with hydrolysates of sugarcane baggasse (SCB), sweet potato peels (SPP) or ripe plantain peels (RPP) at various concentrations while the nitrogen substrates was replaced with extracts of poultry droppings (PP), groundnut pod (GP) or beans bran (BB). Response results observed from single factor optimization were explored as center points to Nwosu et al.; JAMB, 19(2): 1-13, 2019; Article no.JAMB.52290 2 design a model for Response Surface Methodology study. Cell growth was determined from the biomass population of the fermentation broth after 5 days of incubation in a rotary shaker at 120 rpm at 30ºC. EPS was precipitated with pre-chilled ethanol (at 4ºC) from cell-free broth and overnight incubation at 4ºC. Total carbohydrate content was estimated by phenol-sulphuric acid method. Result obtained showed that 2% concentration Hydrolysate of SPP containing medium gave maximum yield of 2.26 g EPS/l of the medium as compared to sucrose containing medium with yield of 1.25 g EPS/l of the medium while highest production yield of 9.46 gEPS/l of the medium was obtained from 10 g/l BB extract medium as compared to yeast extract medium (5.41 gEPS/l). Results indicated that agricultural wastes such as sweet potato peel hydrolysate and bean bran extract could be developed as inexpensive alternative route to synthesize EPS from bacteria than inorganic substrates. Original Research Article

Exopolysaccharides(EPSs) are essential metabolites synthesized and excreted by certain microorganisms in response to extreme condition of pH, temperature, salinity, osmotic stress and other contaminants for survival in such adverse environment. The present study focuses on isolation of exopolysaccharide producing bacteria from extreme environment of oil polluted soil of Ogoni land and marine water of Bonny Island. Screening of EPS producing abilities of the selected isolates were estimated using two approaches viz gravimetric analysis of EPS dry weight and quantification assay for total carbohydrate content by phenol sulphuric acid method. Result revealed that a total of forty (40) different colonies were suspected to produce exopolysaccharide after preliminary screening by selecting thick ropy-like colony formers on agar medium. Secondary screening indicated that twelve (12) isolates produced precipitates above 1000mg/l of total dry weight and eight (8) isolates produced highest EPS yield above 1000mg/l of culture media with carbohydrate content determination. Five isolates with the code WAS1, WAS11, SC6, SOS7 and SOS10 produced significantly higher EPS compared to other bacterial colonies isolated and were termed as most potent EPS producers. These isolates were identified based on 16S rDNA sequence as Providencia stuarti, Escherichia coli, Shewanella chilikensis and Bacillus nealsonii. The result of the present study indicated that these strains have the potentials of producing high exopolysaccharides and can be explored in biotechnological industries.