###### Abstract
Rather than incorporating these aforementioned lignocellulosic biomass treatment methods to supply organic carbon for the first of a two-stage microalgal cultivation process, a novel, more cost-effective, hybrid, thermo-biochemical pre-treatment method involving torrefraction of wheat-straw and subsequent steps was therefore devised. Compared to fast-pyrolysis, torrefraction is a lower-temperature (200-300 \({}^{\circ}\)C) and self-sustaining thermochemical process occurring in an inert, O\({}_{2}\)-less atmosphere [11] that can be conducted in relatively simpler reactors like those previously used by Tawainese farmers [14]. It results not only in a drier, more brittle, and hydrophobic solid biomass to alleviate feedstock logistical issues [15], but also in high-heating value gases (CO, CH\({}_{4}\)) combusted to run it [16], and a liquid condensate containing a mixture of water and carboxylic acids [11]. These torrefraction-derived acids arise mostly from the thermochemical degradation of hemi-cellulose as a by-product, while the pyrolysis-derived acids and phenolic growth inhibitors arise mostly from the lignin depolymerization as an intended bio-oil product [11]. The liquid condensate remaining after torrefraction, requiring less extensive purification due to the lower temperatures, can potentially supply organic carbon (acetate) to a first-stage microalgal culture. In this way, a microalgae that is unable to uptake and/or metabolize directly C\({}_{5}\) sugars (i.e., xylose, mannose, ribose) in hydrolysates can use instead the acetic acid in the condensate obtained from the same hemicellulose fraction. The solid biomass remaining after torrefraction can also potentially be further pre-treated with ozonolysis (O\({}_{3}\)) and soaking in recyclable ammonia, enzymatically hydrolyzed, and purified to supply organic carbon (C\({}_{6}\) sugar glucose) to another first-stage microalgal culture. Compared to the dilute sulfuric acid method, these novel pre-treatment steps involving O\({}_{3}\)/NH\({}_{4}\) to generate hydrolysate were previously shown to require less operation time and milder operating conditions, yielding higher levels of C\({}_{6}\) sugars and lower levels of phenolic inhibitors [10]. Nitrogen and phosphorous nutrients for second-stage, large-scale outdoor open-pond microalgal cultures can be sustainably supplied by effluents from the integrated, bio-gas generating, anaerobic-digestion (AD) of waste. AD using mesophilic or thermophilic bacteria has been widely used instead of energy-intensive aeration-based activated sludge processes to partially treat swine, poultry, and dairy manure waste from farm concentrated animal feeding operations by reducing organic matter and waste volume via fermentative degradation of organic constituents and prevent eutrophication upon its discharge into water bodies [17]. Effluents' unmetabolized inorganic nitrogen (i.e., ammonia) can be used by the microalgae [18], and biogas (i.e., typically a mixture of CH\({}_{4}\), CO\({}_{2}\), H\({}_{2}\)S, and H\({}_{2}\)) can be purified and used for on-site electrical energy to power compressors, pumps, and harvesting centrifuges. Microalgal photosynthesis during cultivation on such waste effluents evolves dissolved O\({}_{2}\) to kill contaminating anaerobes. It is also more metabolically efficient [19] and cost-effective [20] than that using NaNO\({}_{3}\), which represents the most expensive (750-950 USD t\({}^{-1}\)) and concentrated (1.500 g L\({}^{-1}\)) component of the traditional BG-11 growth medium devoid of vitamins. For instance, based on flux balance analysis, nitrates are more metabolically expensive than ammonia because phototrophs, such as _Synechocystis PCC6803_, divert and expend 9 moles of NADPH and ATP to convert 1 mole of NaNO\({}_{3}\) into 1 mole of preferred ammonia [19,21].