Production of Biopolymer from Bacteria - A Review

Polyhydroxyalkanoates (PHA) producers have been found in a variety of ecological niche’s that are naturally or unintentionally exposed to high organic matter or growth limiting substances such as dairy wastes, hydrocarbon contaminated sites, pulp and paper mill wastes, agricultural wastes, activated sludges of treatment plants, rhizosphere, and industrial effluents. Few of them also create extracellular byproducts such as rhamnolipids, extracellular polymeric compounds, and biohydrogen gas. These microbes can use waste materials of various origin as substrates while producing valuable bioproducts such as PHB. As a result, these microbes are industrially important candidates for production; Implementation of an integrated system to separate their by-products (intracellular and extracellular) could be an economical method. In this study, we reviewed several microorganisms that live in diverse environmental situations and are stimulated to collect carbon as polyhydroxyalkanoates granules, as well as variables that influence their production and composition. Ultimately, the current cost of bioplastic manufacture from stored PHA granules can be decreased by investigating capabilities such as dual generation of microorganisms and utilization of wastes as renewable substrate under optimal growth conditions in either a batch or continuous process.

A New Method to Recycle Dairy Waste for the Nutrition of Wheat Plants

Dairy products are vital components of human food, however, they are rapidly spoiled due to their high content of organic matter which encourages the growth of decomposing microbes. The recycling of dairy wastes is an ideal solution to preserve the environment, as it is in line with the principles of sustainable agriculture. In this experiment, an organic fertilizer was extracted from dairy wastes and was used for the nutrition of wheat grown on sandy soils under two-year field studies. The application rate of the extracted organic fertilizer was 8 ton ha−1. Moreover, the same rates of N, P, and K were added from inorganic fertilizers. The extracted organic fertilizer significantly (p < 0.05) enhanced the wheat growth and increased chlorophyll by 11% and 16% in the first and second season, respectively, in comparison to the inorganic fertilization. The extracted organic fertilizer significantly minimized the soil pH from an initial value of 8.00 to 7.05. The tested organic fertilizer increased the uptake of N, P, and K by 55%, 49%, and 51% above the inorganic nutrition, respectively. The wheat straw and grain yield increased by 16% and 29% as a result of the addition of the organic fertilizer extracted from dairy wastes. The dairy wastes organic fertilizer caused a notable improvement in the soil quality. The extracted organic fertilizer was able to supply wheat with its nutrient requirements as it showed a remarkable superiority over the mineral fertilization. The disposal of expired dairy waste can be managed in a way that preserves the environment by converting it to organic fertilizers. Laboratory and field experiments have proven the efficiency of the extracted organic fertilizer in nutrition of wheat plants in sandy soils with low fertility.

Biodegradation of dairy wastes using crude enzymatic extract of Yarrowia lipolytica ATCC 9773

Effluents generated by the food industry have become a serious environmental concern. Bioremediation is a biological process developed as an alternative for the treatment of contaminated areas. In current research, the biodegradation of fat, Biochemical Oxygen Demand (BOD5), Chemical Oxygen Demand (COD) and total solids were evaluated in dairy waste employing enzymatic extract of Yarrowia lipolytica ATCC 9773 as biological agents. All the variables were determined following the specifications of the Standard Methods of the American Water Works Association. Enzymatic extract of Y. lipolytica at different concentrations (8, 12 and 16.0%) was used in a fermentative medium at two pHs (5.0 and 6.5) for 32 h. The highest percentages (%) of fat (82.88), BOD (43.32), COD (44.3) and total solids (13.58) removal were obtained using an inoculum concentration of 16% at pH 5.0 for 32 h of fermentation. These results may have industrial relevance for the reduction of contamination of industrial effluents with high levels of fat and other contaminants.

Manipulating the rumen microbiome to address challenges facing Australasian dairy farming

As dairy production systems expand globally, there is an increasing need to reduce the impact of dairy wastes on the environment by decreasing urinary N output and reducing emissions of green-house gasses (GHG). An understanding of rumen microbiome composition can result in the development of strategies that reduce methane emissions and nitrogen leakage, ultimately lowering the impact of dairying on the environment, while improving animal productivity. The strongest driver of the composition of the rumen microbiome was found to be the diet of the host animal. Thus, dietary manipulation offers a viable solution to alter the microbiome to address present-day challenges faced by the dairy industry. In the present review, we discuss such strategies and provide insight into rumen microbiome changes that have resulted in reduced GHG emissions and improved animal productivity.