Diversity of thermophilic populations during thermophilic aerobic digestion of potato peel slurry

Abstract

To study the diversity of thermophiles during thermophilic aerobic digestion (TAD) of agro-food waste slurries under conditions similar to full-scale processes. Population diversity and development in TAD were studied by standard microbiological techniques and the processes monitored by standard fermentation procedures. Facultative thermophiles were identified as Bacillus coagulans and B. licheniformis, while obligate thermophiles were identified as B. stearothermophilus. They developed rapidly to peaks of 107 to 108 in ≤48 h. Stability of obligate thermophiles increased with process temperatures. Thermophiles were unstable at process pH above or below neutral, but developed rapidly at all aeration rates. Peak populations were higher in the median than at extremes of aeration rates. Obligate thermophiles were unstable at low aeration rates. Process self-heating was higher at lower than at higher aeration rate. Beyond 96 h most thermophiles were present as spores. Limited range of indigenous thermophiles drives TAD of slurry. They develop rapidly and are stable at most digestion conditions. Development and stability of thermophiles in TAD suggest that the process may be operated in a wide range of conditions; and even at short HRT in continuous processes without compromising efficiency

Betaine removal during thermo- and mesophilic aerobic batch biodegradation of beet molasses vinasse: Influence of temperature and pH on the progress and efficiency of the process

“…Further encouragement came from some other studies, which indicate that bacteria of the genus Bacillus are frequently identified in mixed cultures used for the aerobic biodegradation of highstrength industrial effluents at elevated temperature (Lim et al, 2001;Ugwuanyi et al, 2008).…”

Enzymatic Hydrolysis and Ethanol Fermentation of By-Products from Potato Processing Plants

“…Recently, its protective effect against carbon tetrachloride-induced liver injury in rats has been identified (Singh and Rajini, 2008). While banana peel and citrus have been used as media for microbial biomass (Essien et al, 2005) or for enzyme production by fungi (Mamma et al, 2008), most of the by-products from the potato industry are used in animal feed with a combination of other crops (Radunz et al, 2003) or microbial digestion (Ugwuanyi et al, 2008). Plans are being made to use more of the by-products from potato processing.…”

Towards a Microbial Thermoelectric Cell

“…strains, many of which can be isolated from extreme environments such as deep oil wells and the optimal growth of which is 50–60°C. Additionally, these bacteria are reported as able to heat their own culture up to 50–55°C [16]. The perfect candidate for MTC should meet the following criteria: (i) thermoresistant; (ii) strong exothermic ability; (iii) rapid and easy growth; and (iv) an ability to grow and degrade high concentrations of carbon sources.…”