Enhancement of the biogas and biofertilizer production from Opuntia heliabravoana Scheinvar

Prickly Pear (Opuntia spp.) as an Invasive Species and a Potential Fodder Resource for Ruminant Animals

Worldwide, the invasiveness of Opuntia spp. and its impact on various ecosystem services has been recognised especially in semi-arid areas where rainfall is erratic. The semi-arid environments are the habitats of plants which have adapted to be able to grow in severe hot and dry regions. Opuntia spp. normally thrives in conditions of high temperatures, low rainfall, saline soils and it can also adapt and survive in severely degraded soils which have a limited nutrients supply. Its positive impact includes its recognised value as livestock fodder. Opuntia’s adaptability to harsh conditions, high dry matter yield, palatability and significant levels of energy, as well as its availability at a low cost during the dry season, decreases the use of expensive supplements and conventional diets in many areas. There is a need to understand the importance of this invasive Opuntia species when incorporated in animal diets. As a part of its control measures, the use of livestock in controlling the spread of Opuntia may assist in reducing its abundance and invasiveness while at the same time providing a consistent supply of forage during the dry season. Information on its nutritive value, incorporating the species in animal diets and the means to control it must be well understood to recognise the species’ contribution to an ecosystem.

Temperature and extraction methods effects on yields, fatty acids, and tocopherols of prickly pear (Opuntia ficus-indica L.) seed oil of eastern region of Morocco

The present study focuses on the effect of temperature and extraction methods on the yields, chemical quality, fatty acids, and tocopherols of the oil extracted from the seeds of Opuntia ficus-indica, collected in the eastern region of Morocco. Our results revealed the effect of temperature that when we increase the temperature used, the yields also increase; the results also showed that this high temperature does not affect the physicochemical properties, fatty acids, and tocopherols. Thus, the results of this study revealed that the prickly pear is a rich source of oil; the obtained oil yields varied from 12.49%±0.09 for mechanical extraction, 11.46±0.10 for chemical extraction, and 10.52%±0.09 for maceration. The main fatty acids founded in Opuntia ficus-indica are linoleic acid 75.80%±0.10 (chemical), 74.07%±0.14 (maceration), and 71.59%±0.14 (mechanical) and palmitic acid 17.32%±0.02 (chemical), 22.419%±0.06 (maceration), and 26.58%±0.00 (mechanical); prickly pear oil could be classified as a linoleic acid. The physicochemical properties of Opuntia ficus-indica seed oils such as acid index mgKOH/g oil (4,376±0.10, 5.854±0.03, 5.667±0.07), saponification value mgKOH/g oil (181.12 ±0.18, 183.77±1.23, 179.08±3.45), and peroxide value 20milieq/Kg (5.75±0.08, 6±0.06, 5.97±0.04) for mechanical, chemical, and maceration extraction, respectively, density, and refractive index were all found to be in good accordance with quality criteria for both pure and fresh oils. Among the tocopherols found, a high value of γ-tocopherol was detected in mechanical extraction with 502.04±0.76 mg/kg, followed by chemical extraction and maceration with 430.12±0.61mg/kg and 315.47±0.96 mg/kg, respectively.

Identification of potential waste seeds of wildly growing tree species for the production of biogas

In this experimental study, seeds of wild tree species namely Acacia nilotica, Prosopis juliflora, Albizia lebbeck, and Leucaena leucocephala were explored as potential feedstocks for anaerobic digestion and compared with cattle manure which is a commonly used feedstock. These seeds occur abundantly as waste biomass in tropical and subtropical parts of Asia, Africa, and the USA. An experimental investigation was carried out in large 300-L anaerobic digesters under semi-continuous feed mode for 90 days. The average specific methane production yield observed was 0.208 Nm³/kg volatile solids (VS) for A. nilotica, 0.227 Nm³/kg VS for P. juliflora, 0.219 Nm³/kg VS for A. lebbeck and 0.210 Nm³/kg VS for L. leucocephala which was found to be higher than cattle manure's yield of 0.146 Nm³/kg VS. Experimental analysis revealed an average methane content of more than 52% for all the seeds and a total volatile solid mass removal efficiency of 41.60% for A. nilotica, 44.19% for P. juliflora, 43.76% for A. lebbeck, and 41.41% for L. leucocephala which was higher than 29.7% for cattle manure. The experimental investigations showed that they have a higher biogas production potential than cattle manure indicating their huge scope and suitability as alternative feedstocks, and their use can also mitigate the ecological risk seeds pose by growing into invasive trees.

Agricultural waste

The management of agricultural waste has become very important because the inappropriate disposal yields negative effects on the environment. The resource recovery from agricultural waste which converts waste into available resources can reduce the waste and new resource consumption. This review summarizes the 2018 researches of over three hundred scholar papers from several aspects: agricultural waste, and, waste chemical characterization, agricultural waste material, adsorption, waste energy, composting, waste biogas, agricultural waste management, and others.